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Message-ID: <CAMP5XgfyUQT+mQ+SCFhyCSzAWevXUBpTXjpAYS54YTOb-PSpOg@mail.gmail.com>
Date: Tue, 4 Jun 2013 16:58:02 -0700
From: Arve Hjønnevåg <arve@...roid.com>
To: Serban Constantinescu <Serban.Constantinescu@....com>
Cc: LKML <linux-kernel@...r.kernel.org>,
Greg KH <gregkh@...uxfoundation.org>,
Android Kernel Team <kernel-team@...roid.com>,
John Stultz <john.stultz@...aro.org>,
Dave Butcher <Dave.Butcher@....com>
Subject: Re: [PATCH v4 2/6] staging: android: binder: fix binder interface for
64bit compat layer
On Tue, Jun 4, 2013 at 1:54 AM, Serban Constantinescu
<Serban.Constantinescu@....com> wrote:
> On 03/06/13 22:41, Arve Hjønnevåg wrote:
>>
>> On Wed, May 22, 2013 at 3:12 AM, Serban Constantinescu
>> <serban.constantinescu@....com> wrote:
>>>
>>> The changes in this patch will fix the binder interface for use on 64bit
>>> machines and stand as the base of the 64bit compat support. The changes
>>> apply to the structures that are passed between the kernel and
>>> userspace.
>>>
>>> Most of the changes applied mirror the change to struct binder_version
>>> where there is no need for a 64bit wide protocol_version(on 64bit
>>> machines). The change inlines with the existing 32bit userspace(the
>>> structure has the same size) and simplifies the compat layer such that
>>> the same handler can service the BINDER_VERSION ioctl.
>>>
>>> Other changes make use of kernel types as well as user-exportable ones
>>> and fix format specifier issues.
>>>
>>> The changes do not affect existing 32bit ABI.
>>>
>>> Signed-off-by: Serban Constantinescu <serban.constantinescu@....com>
>>> ---
>>> drivers/staging/android/binder.c | 20 ++++++++++----------
>>> drivers/staging/android/binder.h | 8 ++++----
>>> 2 files changed, 14 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/drivers/staging/android/binder.c
>>> b/drivers/staging/android/binder.c
>>> index ce70909..ca79084 100644
>>> --- a/drivers/staging/android/binder.c
>>> +++ b/drivers/staging/android/binder.c
>>> @@ -1271,7 +1271,7 @@ static void
>>> binder_transaction_buffer_release(struct binder_proc *proc,
>>> case BINDER_TYPE_WEAK_HANDLE: {
>>> struct binder_ref *ref = binder_get_ref(proc,
>>> fp->handle);
>>> if (ref == NULL) {
>>> - pr_err("transaction release %d bad handle
>>> %ld\n",
>>> + pr_err("transaction release %d bad handle
>>> %d\n",
>>> debug_id, fp->handle);
>>> break;
>>> }
>>> @@ -1283,13 +1283,13 @@ static void
>>> binder_transaction_buffer_release(struct binder_proc *proc,
>>>
>>> case BINDER_TYPE_FD:
>>> binder_debug(BINDER_DEBUG_TRANSACTION,
>>> - " fd %ld\n", fp->handle);
>>> + " fd %d\n", fp->handle);
>>> if (failed_at)
>>> task_close_fd(proc, fp->handle);
>>> break;
>>>
>>> default:
>>> - pr_err("transaction release %d bad object type
>>> %lx\n",
>>> + pr_err("transaction release %d bad object type
>>> %x\n",
>>> debug_id, fp->type);
>>> break;
>>> }
>>> @@ -1547,7 +1547,7 @@ static void binder_transaction(struct binder_proc
>>> *proc,
>>> case BINDER_TYPE_WEAK_HANDLE: {
>>> struct binder_ref *ref = binder_get_ref(proc,
>>> fp->handle);
>>> if (ref == NULL) {
>>> - binder_user_error("%d:%d got transaction
>>> with invalid handle, %ld\n",
>>> + binder_user_error("%d:%d got transaction
>>> with invalid handle, %d\n",
>>> proc->pid,
>>> thread->pid,
>>> fp->handle);
>>> return_error = BR_FAILED_REPLY;
>>> @@ -1590,13 +1590,13 @@ static void binder_transaction(struct binder_proc
>>> *proc,
>>>
>>> if (reply) {
>>> if (!(in_reply_to->flags &
>>> TF_ACCEPT_FDS)) {
>>> - binder_user_error("%d:%d got
>>> reply with fd, %ld, but target does not allow fds\n",
>>> + binder_user_error("%d:%d got
>>> reply with fd, %d, but target does not allow fds\n",
>>> proc->pid, thread->pid,
>>> fp->handle);
>>> return_error = BR_FAILED_REPLY;
>>> goto err_fd_not_allowed;
>>> }
>>> } else if (!target_node->accept_fds) {
>>> - binder_user_error("%d:%d got transaction
>>> with fd, %ld, but target does not allow fds\n",
>>> + binder_user_error("%d:%d got transaction
>>> with fd, %d, but target does not allow fds\n",
>>> proc->pid, thread->pid,
>>> fp->handle);
>>> return_error = BR_FAILED_REPLY;
>>> goto err_fd_not_allowed;
>>> @@ -1604,7 +1604,7 @@ static void binder_transaction(struct binder_proc
>>> *proc,
>>>
>>> file = fget(fp->handle);
>>> if (file == NULL) {
>>> - binder_user_error("%d:%d got transaction
>>> with invalid fd, %ld\n",
>>> + binder_user_error("%d:%d got transaction
>>> with invalid fd, %d\n",
>>> proc->pid, thread->pid,
>>> fp->handle);
>>> return_error = BR_FAILED_REPLY;
>>> goto err_fget_failed;
>>> @@ -1618,13 +1618,13 @@ static void binder_transaction(struct binder_proc
>>> *proc,
>>> task_fd_install(target_proc, target_fd, file);
>>> trace_binder_transaction_fd(t, fp->handle,
>>> target_fd);
>>> binder_debug(BINDER_DEBUG_TRANSACTION,
>>> - " fd %ld -> %d\n",
>>> fp->handle, target_fd);
>>> + " fd %d -> %d\n", fp->handle,
>>> target_fd);
>>> /* TODO: fput? */
>>> fp->handle = target_fd;
>>> } break;
>>>
>>> default:
>>> - binder_user_error("%d:%d got transaction with
>>> invalid object type, %lx\n",
>>> + binder_user_error("%d:%d got transaction with
>>> invalid object type, %x\n",
>>> proc->pid, thread->pid, fp->type);
>>> return_error = BR_FAILED_REPLY;
>>> goto err_bad_object_type;
>>> @@ -2578,7 +2578,7 @@ static long binder_ioctl(struct file *filp,
>>> unsigned int cmd, unsigned long arg)
>>> goto err;
>>> }
>>> binder_debug(BINDER_DEBUG_READ_WRITE,
>>> - "%d:%d write %zd at %08lx, read %zd at
>>> %08lx\n",
>>> + "%d:%d write %zd at %016lx, read %zd at
>>> %016lx\n",
>>> proc->pid, thread->pid, bwr.write_size,
>>> bwr.write_buffer, bwr.read_size,
>>> bwr.read_buffer);
>>>
>>> diff --git a/drivers/staging/android/binder.h
>>> b/drivers/staging/android/binder.h
>>> index edab249..2f94d16 100644
>>> --- a/drivers/staging/android/binder.h
>>> +++ b/drivers/staging/android/binder.h
>>> @@ -48,13 +48,13 @@ enum {
>>> */
>>> struct flat_binder_object {
>>> /* 8 bytes for large_flat_header. */
>>> - unsigned long type;
>>> - unsigned long flags;
>>> + __u32 type;
>>> + __u32 flags;
>>>
>>> /* 8 bytes of data. */
>>> union {
>>> void __user *binder; /* local object */
>>> - signed long handle; /* remote object */
>>> + __s32 handle; /* remote object */
>>
>>
>> This should be unsigned to match the handle in binder_transaction_data
>> and other uses in the driver, but it is currently also used to pass
>> file descriptors. Perhaps this is better (if sou also change size of
>> the handle in binder_transaction_data to match):
>> __u32 handle; /* remote object */
>> __s32 fd; /* file descriptor */
>
>
> I will add this union and fix any uses of remote object/ file descriptor
> accordingly.
>
>
>>
>>> };
>>>
>>> /* extra data associated with local object */
>>> @@ -78,7 +78,7 @@ struct binder_write_read {
>>> /* Use with BINDER_VERSION, driver fills in fields. */
>>> struct binder_version {
>>> /* driver protocol version -- increment with incompatible change
>>> */
>>> - signed long protocol_version;
>>> + __s32 protocol_version;
>>> };
>>>
>>> /* This is the current protocol version. */
>>> --
>>> 1.7.9.5
>>>
>>
>> I still think the protocol_version size change on 64 bit systems
>> should go after all your other changes that affect 64 bits systems.
>> That way you don't have to change the protocol version later.
>
> At the end of this patch set we will have support for 32/32 and 64/64 binder
> calls. This patch does not add compat support for 64/32 systems and will not
> work for this configuration.
>
> However until we add:
>
>> static const struct file_operations binder_fops = {
>> .owner = THIS_MODULE,
>> .poll = binder_poll,
>> .unlocked_ioctl = binder_ioctl,
>> + .compat_ioctl = binder_ioctl,
>> .mmap = binder_mmap,
>> .open = binder_open,
>> .flush = binder_flush,
>
>
> The return value for any binder ioctl from a 32bit userspace running on top
> of a 64bit kernel will be EINVAL (this happens only for 64/32 systems). Once
> we have the compat layer upstreamed we will add the above change, but until
> that point querying the binder version or any other binder iocall will fail
> (on 64/32).
>
> Let me know if you consider that changing the binder version to use __s32
> when adding the compat layer would be better.
>
If the ioctl fails on for a 32 bit process on a 64 bit kernel, you can
change the size before adding the compat_ioctl, but you need to finish
all the changes that affect a 64/64 system first. You can either split
this change in two or move the entire change to the end of your
patch-set. Can you also post your changes that add 64/32 support?
--
Arve Hjønnevåg
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