From: Greg KH <gregkh@linuxfoundation.org>
To: John Stultz <john.stultz@linaro.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
"Serban Constantinescu" <serban.constantinescu@arm.com>,
"Colin Cross" <ccross@android.com>,
"Arve Hjønnevåg" <arve@android.com>,
"Android Kernel Team" <kernel-team@android.com>
Subject: Re: [PATCH 12/14] staging: binder: Fix ABI for 64bit Android
Date: Tue, 18 Feb 2014 12:32:39 -0800 [thread overview]
Message-ID: <20140218203239.GA18852@kroah.com> (raw)
In-Reply-To: <CALAqxLXYzCkwywS2+besc3Ai1yJc9EuDwDEHquF0OnCjPOXe_Q@mail.gmail.com>
On Tue, Feb 18, 2014 at 12:02:07PM -0800, John Stultz wrote:
> On Tue, Feb 18, 2014 at 11:49 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Tue, Feb 18, 2014 at 11:30:26AM -0800, John Stultz wrote:
> >> On Tue, Feb 18, 2014 at 11:08 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> >> > On Mon, Feb 17, 2014 at 01:58:40PM -0800, John Stultz wrote:
> >> >> From: Serban Constantinescu <serban.constantinescu@arm.com>
> >> >>
> >> >> This patch fixes the ABI for 64bit Android userspace.
> >> >> BC_REQUEST_DEATH_NOTIFICATION and BC_CLEAR_DEATH_NOTIFICATION claim
> >> >> to be using struct binder_ptr_cookie, but they are using a 32bit handle
> >> >> and a pointer.
> >> >>
> >> >> On 32bit systems the payload size is the same as the size of struct
> >> >> binder_ptr_cookie, however for 64bit systems this will differ. This
> >> >> patch adds struct binder_handle_cookie that fixes this issue for 64bit
> >> >> Android.
> >> >>
> >> >> Since there are no 64bit users of this interface that we know of this
> >> >> change should not affect any existing systems.
> >> >
> >> > But you are changing the ioctl structures here, what is that going to
> >> > cause with old programs?
> >>
> >> So I'd be glad for Serban or Arve to clarify, but my understanding
> >> (and as is described in the commit message) is that the assumption is
> >> there are no 64bit binder users at this point, and the ioctl structure
> >> changes are made such that existing 32bit applications are unaffected.
> >
> > How does changing the structure size, and contents, not affect any
> > applications or the kernel code? What am I missing here?
>
> On 32bit pointers and ints are the same size? (Years ago I sat through
> your presentation on this, so I'm worried I'm missing something here
> :)
>
> struct binder_ptr_cookie {
> void *ptr;
> void *cookie;
> };
>
> struct binder_handle_cookie {
> __u32 handle;
> void *cookie;
> } __attribute__((packed));
>
>
> On 32bit systems these are the same size. Now on 64bit systems, this
> changes things, and would break users, but the assumption here is
> there are no pre-existing 64bit binder users.
But you added a field to the existing structure, right? I don't really
remember the patch, it was a few hundred back in my review of stuff
today, sorry...
greg k-h
next prev parent reply other threads:[~2014-02-18 20:31 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-17 21:58 [PATCH 00/14][RFC] Android updates for staging-next John Stultz
2014-02-17 21:58 ` [PATCH 01/14] staging: binder: Fix death notifications John Stultz
2014-02-18 19:02 ` Greg KH
2014-02-18 19:21 ` John Stultz
2014-02-18 19:33 ` Greg KH
2014-02-17 21:58 ` [PATCH 02/14] staging: android: Split uapi out of android_alarm.h John Stultz
2014-02-17 21:58 ` [PATCH 03/14] staging: android: Split uapi out of ashmem.h John Stultz
2014-02-17 21:58 ` [PATCH 04/14] staging: android: split uapi out of sync.h and sw_sync.h John Stultz
2014-02-17 21:58 ` [PATCH 05/14] staging: android: Split uapi out of binder.h John Stultz
2014-02-17 21:58 ` [PATCH 06/14] staging: ion: Create separate heap and client debugfs directories John Stultz
2014-02-17 21:58 ` [PATCH 07/14] staging: ion: Fix debugfs handling of multiple kernel clients John Stultz
2014-02-17 21:58 ` [PATCH 08/14] staging: ion: Store a copy of the client name on client creation John Stultz
2014-02-17 21:58 ` [PATCH 09/14] staging: ion: Make sure all clients are exposed in debugfs John Stultz
2014-02-17 21:58 ` [PATCH 10/14] staging: ion: Move shrinker out of heaps John Stultz
2014-02-17 21:58 ` [PATCH 11/14] staging: ion: Add private buffer flag to skip page pooling on free John Stultz
2014-02-17 21:58 ` [PATCH 12/14] staging: binder: Fix ABI for 64bit Android John Stultz
2014-02-18 19:08 ` Greg KH
2014-02-18 19:30 ` John Stultz
2014-02-18 19:49 ` Greg KH
2014-02-18 20:02 ` John Stultz
2014-02-18 20:32 ` Greg KH [this message]
2014-02-19 0:08 ` Arve Hjønnevåg
2014-02-19 2:13 ` Greg KH
2014-02-17 21:58 ` [PATCH 13/14] staging: binder: Support concurrent 32 bit and 64 bit processes John Stultz
2014-02-18 19:09 ` Greg KH
2014-02-18 19:10 ` Greg KH
2014-02-18 19:43 ` John Stultz
2014-02-17 21:58 ` [PATCH 14/14] staging: binder: Improve Kconfig entry for ANDROID_BINDER_IPC_32BIT John Stultz
2014-02-19 0:18 ` Arve Hjønnevåg
2014-02-19 0:30 ` John Stultz
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