diff mbox

[v4,3/5] tee: generic TEE subsystem

Message ID 1436350592-7732-4-git-send-email-jens.wiklander@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Jens Wiklander July 8, 2015, 10:16 a.m. UTC
Initial patch for generic TEE subsystem.
This subsystem provides:
* Registration/un-registration of TEE drivers.
* Shared memory between normal world and secure world.
* Ioctl interface for interaction with user space.

A TEE (Trusted Execution Environment) driver is a driver that interfaces
with a trusted OS running in some secure environment, for example,
TrustZone on ARM cpus, or a separate secure co-processor etc.

The TEE subsystem can serve a TEE driver for a Global Platform compliant
TEE, but it's not limited to only Global Platform TEEs.

This patch builds on other similar implementations trying to solve
the same problem:
* "optee_linuxdriver" by among others
  Jean-michel DELORME<jean-michel.delorme@st.com> and
  Emmanuel MICHEL <emmanuel.michel@st.com>
* "Generic TrustZone Driver" by Javier González <javier@javigon.com>

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
 Documentation/ioctl/ioctl-number.txt |   1 +
 MAINTAINERS                          |   8 +
 drivers/Kconfig                      |   2 +
 drivers/Makefile                     |   1 +
 drivers/tee/Kconfig                  |   8 +
 drivers/tee/Makefile                 |   3 +
 drivers/tee/tee.c                    | 839 +++++++++++++++++++++++++++++++++++
 drivers/tee/tee_private.h            |  80 ++++
 drivers/tee/tee_shm.c                | 324 ++++++++++++++
 drivers/tee/tee_shm_pool.c           | 133 ++++++
 include/linux/tee_drv.h              | 306 +++++++++++++
 include/uapi/linux/tee.h             | 376 ++++++++++++++++
 12 files changed, 2081 insertions(+)
 create mode 100644 drivers/tee/Kconfig
 create mode 100644 drivers/tee/Makefile
 create mode 100644 drivers/tee/tee.c
 create mode 100644 drivers/tee/tee_private.h
 create mode 100644 drivers/tee/tee_shm.c
 create mode 100644 drivers/tee/tee_shm_pool.c
 create mode 100644 include/linux/tee_drv.h
 create mode 100644 include/uapi/linux/tee.h

Comments

Jason Gunthorpe July 8, 2015, 5:10 p.m. UTC | #1
On Wed, Jul 08, 2015 at 12:16:30PM +0200, Jens Wiklander wrote:

> +static void tee_device_complete_unused(struct kref *kref)
> +{
> +	struct tee_device *teedev;
> +
> +	teedev = container_of(kref, struct tee_device, users);
> +	/* When the mutex is released, no other tee_device_get() will succeed */
> +	teedev->desc = NULL;
> +	complete(&teedev->c_no_users);
> +}
> +
> +void tee_device_put(struct tee_device *teedev)
> +{
> +	mutex_lock(&teedev->mutex);
> +	/* Shouldn't put in this state */
> +	if (!WARN_ON(!teedev->desc))
> +		kref_put(&teedev->users, tee_device_complete_unused);
> +	mutex_unlock(&teedev->mutex);
> +}
> +
> +bool tee_device_get(struct tee_device *teedev)
> +{
> +	mutex_lock(&teedev->mutex);
> +	if (!teedev->desc) {
> +		mutex_unlock(&teedev->mutex);
> +		return false;
> +	}
> +	kref_get(&teedev->users);
> +	mutex_unlock(&teedev->mutex);
> +	return true;
> +}

If you are holding the mutex then you don't really need a kref, just a
simple active count counter.

I've been a bit learly lately about seeing krefs used for something
other than kfree, I've seen a few subtle mistakes in those schemes -
yours looks OK, only because of the lock, and the lock makes the kref
redundant..

> +       cdev_init(&teedev->cdev, &tee_fops);
> +       teedev->cdev.owner = teedesc->owner;

This also needs to set teedev->cdev.kobj.parent.
I'm guessing:

 teedev->cdev.kobj.parent = &teedev->dev.kobj;

TPM had the same mistake..

> +void tee_device_unregister(struct tee_device *teedev)
> +{
> +	if (IS_ERR_OR_NULL(teedev))
> +		return;

See for some general colour on IS_ERR_OR_NULL

https://www.mail-archive.com/linux-omap@vger.kernel.org/msg78030.html

IMHO, you should never, store an ERR pointer into long term storage,
so I wonder why this is like this...

> +	if (teedev->flags & TEE_DEVICE_FLAG_REGISTERED) {
> +		cdev_del(&teedev->cdev);
> +		device_del(&teedev->dev);
> +	}
> +
> +	tee_device_put(teedev);
> +	wait_for_completion(&teedev->c_no_users);

Generally in a scheme like this we'd see open and release get/put the
underlying module handle to prevent driver removal while the char dev
is open. Otherwise module removal will hang here.

Jason
Greg KH July 8, 2015, 9:11 p.m. UTC | #2
On Wed, Jul 08, 2015 at 11:10:26AM -0600, Jason Gunthorpe wrote:
> On Wed, Jul 08, 2015 at 12:16:30PM +0200, Jens Wiklander wrote:
> 
> > +static void tee_device_complete_unused(struct kref *kref)
> > +{
> > +	struct tee_device *teedev;
> > +
> > +	teedev = container_of(kref, struct tee_device, users);
> > +	/* When the mutex is released, no other tee_device_get() will succeed */
> > +	teedev->desc = NULL;
> > +	complete(&teedev->c_no_users);
> > +}
> > +
> > +void tee_device_put(struct tee_device *teedev)
> > +{
> > +	mutex_lock(&teedev->mutex);
> > +	/* Shouldn't put in this state */
> > +	if (!WARN_ON(!teedev->desc))
> > +		kref_put(&teedev->users, tee_device_complete_unused);
> > +	mutex_unlock(&teedev->mutex);
> > +}
> > +
> > +bool tee_device_get(struct tee_device *teedev)
> > +{
> > +	mutex_lock(&teedev->mutex);
> > +	if (!teedev->desc) {
> > +		mutex_unlock(&teedev->mutex);
> > +		return false;
> > +	}
> > +	kref_get(&teedev->users);
> > +	mutex_unlock(&teedev->mutex);
> > +	return true;
> > +}
> 
> If you are holding the mutex then you don't really need a kref, just a
> simple active count counter.
> 
> I've been a bit learly lately about seeing krefs used for something
> other than kfree, I've seen a few subtle mistakes in those schemes -
> yours looks OK, only because of the lock, and the lock makes the kref
> redundant..
> 
> > +       cdev_init(&teedev->cdev, &tee_fops);
> > +       teedev->cdev.owner = teedesc->owner;
> 
> This also needs to set teedev->cdev.kobj.parent.
> I'm guessing:
> 
>  teedev->cdev.kobj.parent = &teedev->dev.kobj;
> 
> TPM had the same mistake..

Really?  As of a few years ago, A cdev's kobject should not be touched
by anything other than the cdev core.  It's not a "real" kobject in that
it is never registered in sysfs, and no one sees it.  I keep meaning to
just use something else one of these days for that structure, as lots of
people get it wrong.  Or has things changed there?

thanks,

greg k-h
Jason Gunthorpe July 8, 2015, 10:26 p.m. UTC | #3
On Wed, Jul 08, 2015 at 02:11:29PM -0700, Greg Kroah-Hartman wrote:
> > > +       cdev_init(&teedev->cdev, &tee_fops);
> > > +       teedev->cdev.owner = teedesc->owner;
> > 
> > This also needs to set teedev->cdev.kobj.parent.
> > I'm guessing:
> > 
> >  teedev->cdev.kobj.parent = &teedev->dev.kobj;
> > 
> > TPM had the same mistake..
> 
> Really?  As of a few years ago, A cdev's kobject should not be touched
> by anything other than the cdev core.  It's not a "real" kobject in that
> it is never registered in sysfs, and no one sees it.  I keep meaning to

Well, when I looked at it, it looked like it was necessary to maintain
the refcount on the memory that is holding cdev.

The basic issue is that cdev_del doesn't seem to be synchronizing.

The use after free race is then something like:

   struct tpm_chip {
 	struct device dev;
	struct cdev cdev;

       CPU0                            CPU1
=================             ======================
tpm_chip = kalloc
cdev_add(&tpm_chip->cdev)
device_add(&tpm_chip->dev)
                                chrdev_open
		                 filp->f_op->open
cdev_del(&tpm_chip->cdev)
device_unregister
   (&tpm_chip->dev)
 kfree(tpm_chip)
		                  tpm_chip = container_of
				 fput
				  cdev_put(.. cdev)

Ie we need cdev to hold a ref on tpm_chip->dev until cdev_put is
called.

> just use something else one of these days for that structure, as lots of
> people get it wrong.  Or has things changed there?

Not recently, but this is the commit:

commit 2f0157f13f42800aa3d9017ebb0fb80a65f7b2de
Author: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date:   Sun Oct 21 17:57:19 2012 -0700

    char_dev: pin parent kobject
    
    In certain cases (for example when a cdev structure is embedded into
    another object whose lifetime is controlled by a separate kobject) it is
    beneficial to tie lifetime of another object to the lifetime of
    character device so that related object is not freed until after
    char_dev object is freed.
    
    To achieve this let's pin kobject's parent when doing cdev_add() and
    unpin when last reference to cdev structure is being released.
    
    Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
    Acked-by: Al Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It doesn't seem the be the best situation, this is the 3rd time this
week I've noticed cdev with a kalloc'd struct being used improperly.

Perhaps cdev_init should accept the module and kref parent as an
argument?

Jason
Greg KH July 8, 2015, 10:33 p.m. UTC | #4
On Wed, Jul 08, 2015 at 04:26:49PM -0600, Jason Gunthorpe wrote:
> On Wed, Jul 08, 2015 at 02:11:29PM -0700, Greg Kroah-Hartman wrote:
> > > > +       cdev_init(&teedev->cdev, &tee_fops);
> > > > +       teedev->cdev.owner = teedesc->owner;
> > > 
> > > This also needs to set teedev->cdev.kobj.parent.
> > > I'm guessing:
> > > 
> > >  teedev->cdev.kobj.parent = &teedev->dev.kobj;
> > > 
> > > TPM had the same mistake..
> > 
> > Really?  As of a few years ago, A cdev's kobject should not be touched
> > by anything other than the cdev core.  It's not a "real" kobject in that
> > it is never registered in sysfs, and no one sees it.  I keep meaning to
> 
> Well, when I looked at it, it looked like it was necessary to maintain
> the refcount on the memory that is holding cdev.
> 
> The basic issue is that cdev_del doesn't seem to be synchronizing.
> 
> The use after free race is then something like:
> 
>    struct tpm_chip {
>  	struct device dev;
> 	struct cdev cdev;

Oops, right there's your problem.  You can't have two reference counted
objects trying to manage the memory of a single structure.  No matter
what you do, it's going to be a pain to deal with this, so don't :)

> 
>        CPU0                            CPU1
> =================             ======================
> tpm_chip = kalloc
> cdev_add(&tpm_chip->cdev)
> device_add(&tpm_chip->dev)
>                                 chrdev_open
> 		                 filp->f_op->open
> cdev_del(&tpm_chip->cdev)
> device_unregister
>    (&tpm_chip->dev)
>  kfree(tpm_chip)
> 		                  tpm_chip = container_of
> 				 fput
> 				  cdev_put(.. cdev)
> 
> Ie we need cdev to hold a ref on tpm_chip->dev until cdev_put is
> called.

No, separate them, make the cdev a pointer and all should be fine.

> > just use something else one of these days for that structure, as lots of
> > people get it wrong.  Or has things changed there?
> 
> Not recently, but this is the commit:
> 
> commit 2f0157f13f42800aa3d9017ebb0fb80a65f7b2de
> Author: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Date:   Sun Oct 21 17:57:19 2012 -0700
> 
>     char_dev: pin parent kobject
>     
>     In certain cases (for example when a cdev structure is embedded into
>     another object whose lifetime is controlled by a separate kobject) it is
>     beneficial to tie lifetime of another object to the lifetime of
>     character device so that related object is not freed until after
>     char_dev object is freed.
>     
>     To achieve this let's pin kobject's parent when doing cdev_add() and
>     unpin when last reference to cdev structure is being released.
>     
>     Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>     Acked-by: Al Viro <viro@zeniv.linux.org.uk>
>     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> 
> It doesn't seem the be the best situation, this is the 3rd time this
> week I've noticed cdev with a kalloc'd struct being used improperly.
> 
> Perhaps cdev_init should accept the module and kref parent as an
> argument?

Oh yeah, that commit :(

If you know _exactly_ what you are doing, you can get away with this,
but I strongly recommend not doing that.  As proof of that, in some new
code I'm working on, I did not do this, just because I'm not smart
enough to ensure it's all working properly...

thanks,

greg k-h
Jason Gunthorpe July 8, 2015, 11:16 p.m. UTC | #5
On Wed, Jul 08, 2015 at 03:33:25PM -0700, Greg Kroah-Hartman wrote:
> > The basic issue is that cdev_del doesn't seem to be synchronizing.
> > 
> > The use after free race is then something like:
> > 
> >    struct tpm_chip {
> >  	struct device dev;
> > 	struct cdev cdev;
> 
> Oops, right there's your problem.  You can't have two reference counted
> objects trying to manage the memory of a single structure.  No matter
> what you do, it's going to be a pain to deal with this, so don't :)

Sure, generally, yes, but that isn't done for no reason, it is to make
open straightforward:

static int tpm_open(struct inode *inode, struct file *file)
{
	struct tpm_chip *chip =
		container_of(inode->i_cdev, struct tpm_chip, cdev);

We need to recover the tpm_chip associated with the char device
node, in a way that is holding a kref on it, without racing with
cdev_del/etc

This scheme does mean that if we have a struct file we have a kref on
the cdev, and if we have cdev then we have a kref on the tpm_chip,
which is really easy to use properly.

> > Ie we need cdev to hold a ref on tpm_chip->dev until cdev_put is
> > called.
> 
> No, separate them, make the cdev a pointer and all should be fine.

Okay, cdev_alloc takes care of the cdev lifetime.

Do you have a simple solution to replace container_of as well?

What would you think about something like:

 cdev_alloc(&chip->dev.kref)

?

Jason
Dmitry Torokhov July 8, 2015, 11:28 p.m. UTC | #6
On Wed, Jul 08, 2015 at 03:33:25PM -0700, Greg Kroah-Hartman wrote:
> On Wed, Jul 08, 2015 at 04:26:49PM -0600, Jason Gunthorpe wrote:
> > On Wed, Jul 08, 2015 at 02:11:29PM -0700, Greg Kroah-Hartman wrote:
> > > > > +       cdev_init(&teedev->cdev, &tee_fops);
> > > > > +       teedev->cdev.owner = teedesc->owner;
> > > > 
> > > > This also needs to set teedev->cdev.kobj.parent.
> > > > I'm guessing:
> > > > 
> > > >  teedev->cdev.kobj.parent = &teedev->dev.kobj;
> > > > 
> > > > TPM had the same mistake..
> > > 
> > > Really?  As of a few years ago, A cdev's kobject should not be touched
> > > by anything other than the cdev core.  It's not a "real" kobject in that
> > > it is never registered in sysfs, and no one sees it.  I keep meaning to
> > 
> > Well, when I looked at it, it looked like it was necessary to maintain
> > the refcount on the memory that is holding cdev.
> > 
> > The basic issue is that cdev_del doesn't seem to be synchronizing.
> > 
> > The use after free race is then something like:
> > 
> >    struct tpm_chip {
> >  	struct device dev;
> > 	struct cdev cdev;
> 
> Oops, right there's your problem.  You can't have two reference counted
> objects trying to manage the memory of a single structure.  No matter
> what you do, it's going to be a pain to deal with this, so don't :)
> 
> > 
> >        CPU0                            CPU1
> > =================             ======================
> > tpm_chip = kalloc
> > cdev_add(&tpm_chip->cdev)
> > device_add(&tpm_chip->dev)
> >                                 chrdev_open
> > 		                 filp->f_op->open
> > cdev_del(&tpm_chip->cdev)
> > device_unregister
> >    (&tpm_chip->dev)
> >  kfree(tpm_chip)
> > 		                  tpm_chip = container_of
> > 				 fput
> > 				  cdev_put(.. cdev)
> > 
> > Ie we need cdev to hold a ref on tpm_chip->dev until cdev_put is
> > called.
> 
> No, separate them, make the cdev a pointer and all should be fine.
> 
> > > just use something else one of these days for that structure, as lots of
> > > people get it wrong.  Or has things changed there?
> > 
> > Not recently, but this is the commit:
> > 
> > commit 2f0157f13f42800aa3d9017ebb0fb80a65f7b2de
> > Author: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > Date:   Sun Oct 21 17:57:19 2012 -0700
> > 
> >     char_dev: pin parent kobject
> >     
> >     In certain cases (for example when a cdev structure is embedded into
> >     another object whose lifetime is controlled by a separate kobject) it is
> >     beneficial to tie lifetime of another object to the lifetime of
> >     character device so that related object is not freed until after
> >     char_dev object is freed.
> >     
> >     To achieve this let's pin kobject's parent when doing cdev_add() and
> >     unpin when last reference to cdev structure is being released.
> >     
> >     Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> >     Acked-by: Al Viro <viro@zeniv.linux.org.uk>
> >     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> > 
> > It doesn't seem the be the best situation, this is the 3rd time this
> > week I've noticed cdev with a kalloc'd struct being used improperly.
> > 
> > Perhaps cdev_init should accept the module and kref parent as an
> > argument?
> 
> Oh yeah, that commit :(
> 
> If you know _exactly_ what you are doing, you can get away with this,
> but I strongly recommend not doing that.  As proof of that, in some new
> code I'm working on, I did not do this, just because I'm not smart
> enough to ensure it's all working properly...

I know you like to allocate everything separately and access it via
pointers (ala device_create) but cdevs explicitly allow embedding them
into other structures (cdev_init vs cdev_alloc). I do not think there is
anything wrong with this, as well as there is nothing wrong in embedding
a struct device into other structures, but it does require coordinating
lifetime rules and selecting a "master" kobject. I think having
cdev_init accept such "master" kobject would bring author's attention to
the issue and avoid such mistakes in the future.

Thanks.
Greg KH July 8, 2015, 11:52 p.m. UTC | #7
On Wed, Jul 08, 2015 at 04:28:26PM -0700, Dmitry Torokhov wrote:
> On Wed, Jul 08, 2015 at 03:33:25PM -0700, Greg Kroah-Hartman wrote:
> > On Wed, Jul 08, 2015 at 04:26:49PM -0600, Jason Gunthorpe wrote:
> > > On Wed, Jul 08, 2015 at 02:11:29PM -0700, Greg Kroah-Hartman wrote:
> > > > > > +       cdev_init(&teedev->cdev, &tee_fops);
> > > > > > +       teedev->cdev.owner = teedesc->owner;
> > > > > 
> > > > > This also needs to set teedev->cdev.kobj.parent.
> > > > > I'm guessing:
> > > > > 
> > > > >  teedev->cdev.kobj.parent = &teedev->dev.kobj;
> > > > > 
> > > > > TPM had the same mistake..
> > > > 
> > > > Really?  As of a few years ago, A cdev's kobject should not be touched
> > > > by anything other than the cdev core.  It's not a "real" kobject in that
> > > > it is never registered in sysfs, and no one sees it.  I keep meaning to
> > > 
> > > Well, when I looked at it, it looked like it was necessary to maintain
> > > the refcount on the memory that is holding cdev.
> > > 
> > > The basic issue is that cdev_del doesn't seem to be synchronizing.
> > > 
> > > The use after free race is then something like:
> > > 
> > >    struct tpm_chip {
> > >  	struct device dev;
> > > 	struct cdev cdev;
> > 
> > Oops, right there's your problem.  You can't have two reference counted
> > objects trying to manage the memory of a single structure.  No matter
> > what you do, it's going to be a pain to deal with this, so don't :)
> > 
> > > 
> > >        CPU0                            CPU1
> > > =================             ======================
> > > tpm_chip = kalloc
> > > cdev_add(&tpm_chip->cdev)
> > > device_add(&tpm_chip->dev)
> > >                                 chrdev_open
> > > 		                 filp->f_op->open
> > > cdev_del(&tpm_chip->cdev)
> > > device_unregister
> > >    (&tpm_chip->dev)
> > >  kfree(tpm_chip)
> > > 		                  tpm_chip = container_of
> > > 				 fput
> > > 				  cdev_put(.. cdev)
> > > 
> > > Ie we need cdev to hold a ref on tpm_chip->dev until cdev_put is
> > > called.
> > 
> > No, separate them, make the cdev a pointer and all should be fine.
> > 
> > > > just use something else one of these days for that structure, as lots of
> > > > people get it wrong.  Or has things changed there?
> > > 
> > > Not recently, but this is the commit:
> > > 
> > > commit 2f0157f13f42800aa3d9017ebb0fb80a65f7b2de
> > > Author: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > > Date:   Sun Oct 21 17:57:19 2012 -0700
> > > 
> > >     char_dev: pin parent kobject
> > >     
> > >     In certain cases (for example when a cdev structure is embedded into
> > >     another object whose lifetime is controlled by a separate kobject) it is
> > >     beneficial to tie lifetime of another object to the lifetime of
> > >     character device so that related object is not freed until after
> > >     char_dev object is freed.
> > >     
> > >     To achieve this let's pin kobject's parent when doing cdev_add() and
> > >     unpin when last reference to cdev structure is being released.
> > >     
> > >     Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > >     Acked-by: Al Viro <viro@zeniv.linux.org.uk>
> > >     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> > > 
> > > It doesn't seem the be the best situation, this is the 3rd time this
> > > week I've noticed cdev with a kalloc'd struct being used improperly.
> > > 
> > > Perhaps cdev_init should accept the module and kref parent as an
> > > argument?
> > 
> > Oh yeah, that commit :(
> > 
> > If you know _exactly_ what you are doing, you can get away with this,
> > but I strongly recommend not doing that.  As proof of that, in some new
> > code I'm working on, I did not do this, just because I'm not smart
> > enough to ensure it's all working properly...
> 
> I know you like to allocate everything separately and access it via
> pointers (ala device_create) but cdevs explicitly allow embedding them
> into other structures (cdev_init vs cdev_alloc). I do not think there is
> anything wrong with this, as well as there is nothing wrong in embedding
> a struct device into other structures, but it does require coordinating
> lifetime rules and selecting a "master" kobject. I think having
> cdev_init accept such "master" kobject would bring author's attention to
> the issue and avoid such mistakes in the future.

Embedding cdevs into other structures is great, I like that.  What I
don't like is having two different reference counts for the same
structure based on the lifetime rules of two different embedded
structures.  That's a very difficult thing to get right and I would
argue, is something that should almost never be done.

thanks,

greg k-h
Greg KH July 8, 2015, 11:53 p.m. UTC | #8
On Wed, Jul 08, 2015 at 05:16:12PM -0600, Jason Gunthorpe wrote:
> On Wed, Jul 08, 2015 at 03:33:25PM -0700, Greg Kroah-Hartman wrote:
> > > The basic issue is that cdev_del doesn't seem to be synchronizing.
> > > 
> > > The use after free race is then something like:
> > > 
> > >    struct tpm_chip {
> > >  	struct device dev;
> > > 	struct cdev cdev;
> > 
> > Oops, right there's your problem.  You can't have two reference counted
> > objects trying to manage the memory of a single structure.  No matter
> > what you do, it's going to be a pain to deal with this, so don't :)
> 
> Sure, generally, yes, but that isn't done for no reason, it is to make
> open straightforward:
> 
> static int tpm_open(struct inode *inode, struct file *file)
> {
> 	struct tpm_chip *chip =
> 		container_of(inode->i_cdev, struct tpm_chip, cdev);
> 
> We need to recover the tpm_chip associated with the char device
> node, in a way that is holding a kref on it, without racing with
> cdev_del/etc
> 
> This scheme does mean that if we have a struct file we have a kref on
> the cdev, and if we have cdev then we have a kref on the tpm_chip,
> which is really easy to use properly.
> 
> > > Ie we need cdev to hold a ref on tpm_chip->dev until cdev_put is
> > > called.
> > 
> > No, separate them, make the cdev a pointer and all should be fine.
> 
> Okay, cdev_alloc takes care of the cdev lifetime.
> 
> Do you have a simple solution to replace container_of as well?
> 
> What would you think about something like:
> 
>  cdev_alloc(&chip->dev.kref)

Just pick either the cdev to handle the lifetime rules, or the struct
device, you'll still need a container_of().  Just don't do both as odds
are the lifetime rules is going to get really hard to debug and ensure
that everything is correct on the shutdown/release path.

thanks,

greg k-h
Dmitry Torokhov July 9, 2015, 12:47 a.m. UTC | #9
On Wed, Jul 08, 2015 at 04:53:21PM -0700, Greg Kroah-Hartman wrote:
> On Wed, Jul 08, 2015 at 05:16:12PM -0600, Jason Gunthorpe wrote:
> > On Wed, Jul 08, 2015 at 03:33:25PM -0700, Greg Kroah-Hartman wrote:
> > > > The basic issue is that cdev_del doesn't seem to be synchronizing.
> > > > 
> > > > The use after free race is then something like:
> > > > 
> > > >    struct tpm_chip {
> > > >  	struct device dev;
> > > > 	struct cdev cdev;
> > > 
> > > Oops, right there's your problem.  You can't have two reference counted
> > > objects trying to manage the memory of a single structure.  No matter
> > > what you do, it's going to be a pain to deal with this, so don't :)
> > 
> > Sure, generally, yes, but that isn't done for no reason, it is to make
> > open straightforward:
> > 
> > static int tpm_open(struct inode *inode, struct file *file)
> > {
> > 	struct tpm_chip *chip =
> > 		container_of(inode->i_cdev, struct tpm_chip, cdev);
> > 
> > We need to recover the tpm_chip associated with the char device
> > node, in a way that is holding a kref on it, without racing with
> > cdev_del/etc
> > 
> > This scheme does mean that if we have a struct file we have a kref on
> > the cdev, and if we have cdev then we have a kref on the tpm_chip,
> > which is really easy to use properly.
> > 
> > > > Ie we need cdev to hold a ref on tpm_chip->dev until cdev_put is
> > > > called.
> > > 
> > > No, separate them, make the cdev a pointer and all should be fine.
> > 
> > Okay, cdev_alloc takes care of the cdev lifetime.
> > 
> > Do you have a simple solution to replace container_of as well?
> > 
> > What would you think about something like:
> > 
> >  cdev_alloc(&chip->dev.kref)
> 
> Just pick either the cdev to handle the lifetime rules, or the struct
> device, you'll still need a container_of().  Just don't do both as odds
> are the lifetime rules is going to get really hard to debug and ensure
> that everything is correct on the shutdown/release path.

It is not that simple. The issue is that we need to ensure that cdev
does not outlive the structure that represents the device, otherwise it
may disappear while cdev code tries to access it. So we need a way to
pin the "main" structure in memory until cdev is gone. But as I
mentioned in [1] cdev is "sealed" and does not give us a way of hooking
into add/release so that we can try to pin the object we need. And given
that the main driver model primitive is kobject even if we "unseal" cdev
everyone will end up doing pretty much what the above commit did.

Thanks.
Dmitry Torokhov July 9, 2015, 12:56 a.m. UTC | #10
On Wed, Jul 08, 2015 at 04:52:03PM -0700, Greg Kroah-Hartman wrote:
> On Wed, Jul 08, 2015 at 04:28:26PM -0700, Dmitry Torokhov wrote:
> > On Wed, Jul 08, 2015 at 03:33:25PM -0700, Greg Kroah-Hartman wrote:
> > > On Wed, Jul 08, 2015 at 04:26:49PM -0600, Jason Gunthorpe wrote:
> > > > On Wed, Jul 08, 2015 at 02:11:29PM -0700, Greg Kroah-Hartman wrote:
> > > > > > > +       cdev_init(&teedev->cdev, &tee_fops);
> > > > > > > +       teedev->cdev.owner = teedesc->owner;
> > > > > > 
> > > > > > This also needs to set teedev->cdev.kobj.parent.
> > > > > > I'm guessing:
> > > > > > 
> > > > > >  teedev->cdev.kobj.parent = &teedev->dev.kobj;
> > > > > > 
> > > > > > TPM had the same mistake..
> > > > > 
> > > > > Really?  As of a few years ago, A cdev's kobject should not be touched
> > > > > by anything other than the cdev core.  It's not a "real" kobject in that
> > > > > it is never registered in sysfs, and no one sees it.  I keep meaning to
> > > > 
> > > > Well, when I looked at it, it looked like it was necessary to maintain
> > > > the refcount on the memory that is holding cdev.
> > > > 
> > > > The basic issue is that cdev_del doesn't seem to be synchronizing.
> > > > 
> > > > The use after free race is then something like:
> > > > 
> > > >    struct tpm_chip {
> > > >  	struct device dev;
> > > > 	struct cdev cdev;
> > > 
> > > Oops, right there's your problem.  You can't have two reference counted
> > > objects trying to manage the memory of a single structure.  No matter
> > > what you do, it's going to be a pain to deal with this, so don't :)
> > > 
> > > > 
> > > >        CPU0                            CPU1
> > > > =================             ======================
> > > > tpm_chip = kalloc
> > > > cdev_add(&tpm_chip->cdev)
> > > > device_add(&tpm_chip->dev)
> > > >                                 chrdev_open
> > > > 		                 filp->f_op->open
> > > > cdev_del(&tpm_chip->cdev)
> > > > device_unregister
> > > >    (&tpm_chip->dev)
> > > >  kfree(tpm_chip)
> > > > 		                  tpm_chip = container_of
> > > > 				 fput
> > > > 				  cdev_put(.. cdev)
> > > > 
> > > > Ie we need cdev to hold a ref on tpm_chip->dev until cdev_put is
> > > > called.
> > > 
> > > No, separate them, make the cdev a pointer and all should be fine.
> > > 
> > > > > just use something else one of these days for that structure, as lots of
> > > > > people get it wrong.  Or has things changed there?
> > > > 
> > > > Not recently, but this is the commit:
> > > > 
> > > > commit 2f0157f13f42800aa3d9017ebb0fb80a65f7b2de
> > > > Author: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > > > Date:   Sun Oct 21 17:57:19 2012 -0700
> > > > 
> > > >     char_dev: pin parent kobject
> > > >     
> > > >     In certain cases (for example when a cdev structure is embedded into
> > > >     another object whose lifetime is controlled by a separate kobject) it is
> > > >     beneficial to tie lifetime of another object to the lifetime of
> > > >     character device so that related object is not freed until after
> > > >     char_dev object is freed.
> > > >     
> > > >     To achieve this let's pin kobject's parent when doing cdev_add() and
> > > >     unpin when last reference to cdev structure is being released.
> > > >     
> > > >     Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > > >     Acked-by: Al Viro <viro@zeniv.linux.org.uk>
> > > >     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> > > > 
> > > > It doesn't seem the be the best situation, this is the 3rd time this
> > > > week I've noticed cdev with a kalloc'd struct being used improperly.
> > > > 
> > > > Perhaps cdev_init should accept the module and kref parent as an
> > > > argument?
> > > 
> > > Oh yeah, that commit :(
> > > 
> > > If you know _exactly_ what you are doing, you can get away with this,
> > > but I strongly recommend not doing that.  As proof of that, in some new
> > > code I'm working on, I did not do this, just because I'm not smart
> > > enough to ensure it's all working properly...
> > 
> > I know you like to allocate everything separately and access it via
> > pointers (ala device_create) but cdevs explicitly allow embedding them
> > into other structures (cdev_init vs cdev_alloc). I do not think there is
> > anything wrong with this, as well as there is nothing wrong in embedding
> > a struct device into other structures, but it does require coordinating
> > lifetime rules and selecting a "master" kobject. I think having
> > cdev_init accept such "master" kobject would bring author's attention to
> > the issue and avoid such mistakes in the future.
> 
> Embedding cdevs into other structures is great, I like that.  What I
> don't like is having two different reference counts for the same
> structure based on the lifetime rules of two different embedded
> structures.  That's a very difficult thing to get right and I would
> argue, is something that should almost never be done.

I think if we stop thinking about reference counts in the context of
releasing memory that will clear the issue. The reference count for cdev
is for cdev alone. The reference count for struct device is for the
struct device. What happens when either one or both of them drop to 0 is
up to the driver controlling the objects.

Thanks.
Jens Wiklander July 9, 2015, 12:49 p.m. UTC | #11
On Wed, Jul 08, 2015 at 11:10:26AM -0600, Jason Gunthorpe wrote:
> On Wed, Jul 08, 2015 at 12:16:30PM +0200, Jens Wiklander wrote:
> 
> > +static void tee_device_complete_unused(struct kref *kref)
> > +{
> > +	struct tee_device *teedev;
> > +
> > +	teedev = container_of(kref, struct tee_device, users);
> > +	/* When the mutex is released, no other tee_device_get() will succeed */
> > +	teedev->desc = NULL;
> > +	complete(&teedev->c_no_users);
> > +}
> > +
> > +void tee_device_put(struct tee_device *teedev)
> > +{
> > +	mutex_lock(&teedev->mutex);
> > +	/* Shouldn't put in this state */
> > +	if (!WARN_ON(!teedev->desc))
> > +		kref_put(&teedev->users, tee_device_complete_unused);
> > +	mutex_unlock(&teedev->mutex);
> > +}
> > +
> > +bool tee_device_get(struct tee_device *teedev)
> > +{
> > +	mutex_lock(&teedev->mutex);
> > +	if (!teedev->desc) {
> > +		mutex_unlock(&teedev->mutex);
> > +		return false;
> > +	}
> > +	kref_get(&teedev->users);
> > +	mutex_unlock(&teedev->mutex);
> > +	return true;
> > +}
> 
> If you are holding the mutex then you don't really need a kref, just a
> simple active count counter.
> 
> I've been a bit learly lately about seeing krefs used for something
> other than kfree, I've seen a few subtle mistakes in those schemes -
> yours looks OK, only because of the lock, and the lock makes the kref
> redundant..

Thanks, I'll fix.

> 
> > +       cdev_init(&teedev->cdev, &tee_fops);
> > +       teedev->cdev.owner = teedesc->owner;
> 
> This also needs to set teedev->cdev.kobj.parent.
> I'm guessing:
> 
>  teedev->cdev.kobj.parent = &teedev->dev.kobj;
> 
> TPM had the same mistake..

OK. This triggered a discussion, from what I understand the outcome
is that what you're suggesting is the right thing to do here.

> 
> > +void tee_device_unregister(struct tee_device *teedev)
> > +{
> > +	if (IS_ERR_OR_NULL(teedev))
> > +		return;
> 
> See for some general colour on IS_ERR_OR_NULL
> 
> https://www.mail-archive.com/linux-omap@vger.kernel.org/msg78030.html
> 
> IMHO, you should never, store an ERR pointer into long term storage,
> so I wonder why this is like this...

OK, I'll replace the IS_ERR_OR_NULL with !teedev and only store a real
pointer or NULL here.

> 
> > +	if (teedev->flags & TEE_DEVICE_FLAG_REGISTERED) {
> > +		cdev_del(&teedev->cdev);
> > +		device_del(&teedev->dev);
> > +	}
> > +
> > +	tee_device_put(teedev);
> > +	wait_for_completion(&teedev->c_no_users);
> 
> Generally in a scheme like this we'd see open and release get/put the
> underlying module handle to prevent driver removal while the char dev
> is open. Otherwise module removal will hang here.

I'm perhaps misunderstanding you. While the cdev has any open file
descriptors rmmod will fail with "Resource temporarily unavailable"
because of fops_get() in chrdev_open().

tee_device_get()/put() deals with detaching of the driver, I see no
other way than blocking here once the detaching has been triggered.

--
Thanks,
Jens
Jason Gunthorpe July 9, 2015, 6:25 p.m. UTC | #12
On Thu, Jul 09, 2015 at 02:49:08PM +0200, Jens Wiklander wrote:
> > Generally in a scheme like this we'd see open and release get/put the
> > underlying module handle to prevent driver removal while the char dev
> > is open. Otherwise module removal will hang here.
> 
> I'm perhaps misunderstanding you. While the cdev has any open file
> descriptors rmmod will fail with "Resource temporarily unavailable"
> because of fops_get() in chrdev_open().

Hmm, I see, you've done this:

+       cdev_init(&teedev->cdev, &tee_fops);
+       teedev->cdev.owner = teedesc->owner;

And owner here is the driver module? Interesting.. Looks OK..

Jason
diff mbox

Patch

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 51f4221..f54dfc02 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -301,6 +301,7 @@  Code  Seq#(hex)	Include File		Comments
 0xA3	80-8F	Port ACL		in development:
 					<mailto:tlewis@mindspring.com>
 0xA3	90-9F	linux/dtlk.h
+0xA4	00-1F	uapi/linux/tee.h	Generic TEE subsystem
 0xAB	00-1F	linux/nbd.h
 0xAC	00-1F	linux/raw.h
 0xAD	00	Netfilter device	in development:
diff --git a/MAINTAINERS b/MAINTAINERS
index d8afd29..869635f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8634,6 +8634,14 @@  S:	Maintained
 F:	include/linux/mmc/dw_mmc.h
 F:	drivers/mmc/host/dw_mmc*
 
+TEE SUBSYSTEM
+M:	Jens Wiklander <jens.wiklander@linaro.org>
+M:	Javier González <javier@javigon.com>
+S:	Maintained
+F:	include/linux/tee_drv.h
+F:	include/uapi/linux/tee.h
+F:	drivers/tee/
+
 THUNDERBOLT DRIVER
 M:	Andreas Noever <andreas.noever@gmail.com>
 S:	Maintained
diff --git a/drivers/Kconfig b/drivers/Kconfig
index c0cc96b..7510f69 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -182,4 +182,6 @@  source "drivers/thunderbolt/Kconfig"
 
 source "drivers/android/Kconfig"
 
+source "drivers/tee/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 46d2554..852f0af 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -165,3 +165,4 @@  obj-$(CONFIG_RAS)		+= ras/
 obj-$(CONFIG_THUNDERBOLT)	+= thunderbolt/
 obj-$(CONFIG_CORESIGHT)		+= hwtracing/coresight/
 obj-$(CONFIG_ANDROID)		+= android/
+obj-$(CONFIG_TEE)		+= tee/
diff --git a/drivers/tee/Kconfig b/drivers/tee/Kconfig
new file mode 100644
index 0000000..64a8cd7
--- /dev/null
+++ b/drivers/tee/Kconfig
@@ -0,0 +1,8 @@ 
+# Generic Trusted Execution Environment Configuration
+config TEE
+	bool "Trusted Execution Environment support"
+	default n
+	select DMA_SHARED_BUFFER
+	help
+	  This implements a generic interface towards a Trusted Execution
+	  Environment (TEE).
diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile
new file mode 100644
index 0000000..60d2dab
--- /dev/null
+++ b/drivers/tee/Makefile
@@ -0,0 +1,3 @@ 
+obj-y += tee.o
+obj-y += tee_shm.o
+obj-y += tee_shm_pool.o
diff --git a/drivers/tee/tee.c b/drivers/tee/tee.c
new file mode 100644
index 0000000..9dca143
--- /dev/null
+++ b/drivers/tee/tee.c
@@ -0,0 +1,839 @@ 
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/tee_drv.h>
+#include "tee_private.h"
+
+#define TEE_NUM_DEVICES	32
+
+#define TEE_IOCTL_PARAM_SIZE(x) (sizeof(struct tee_param) * (x))
+
+/*
+ * Unprivileged devices in the in the lower half range and privileged
+ * devices in the upper half range.
+ */
+static DECLARE_BITMAP(dev_mask, TEE_NUM_DEVICES);
+static DEFINE_SPINLOCK(driver_lock);
+
+static struct class *tee_class;
+static dev_t tee_devt;
+
+static int tee_open(struct inode *inode, struct file *filp)
+{
+	int rc;
+	struct tee_device *teedev;
+	struct tee_context *ctx;
+
+	teedev = container_of(inode->i_cdev, struct tee_device, cdev);
+	if (!tee_device_get(teedev))
+		return -EINVAL;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->teedev = teedev;
+	filp->private_data = ctx;
+	rc = teedev->desc->ops->open(ctx);
+	if (rc) {
+		kfree(ctx);
+		tee_device_put(teedev);
+	}
+	return rc;
+}
+
+static int tee_release(struct inode *inode, struct file *filp)
+{
+	struct tee_context *ctx = filp->private_data;
+	struct tee_device *teedev = ctx->teedev;
+
+	ctx->teedev->desc->ops->release(ctx);
+	kfree(ctx);
+	tee_device_put(teedev);
+	return 0;
+}
+
+static int tee_ioctl_version(struct tee_context *ctx,
+		struct tee_ioctl_version_data __user *uvers)
+{
+	struct tee_ioctl_version_data vers;
+
+	ctx->teedev->desc->ops->get_version(ctx, &vers);
+	if (copy_to_user(uvers, &vers, sizeof(vers)))
+		return -EFAULT;
+	return 0;
+}
+
+static int tee_ioctl_shm_alloc(struct tee_context *ctx,
+		struct tee_ioctl_shm_alloc_data __user *udata)
+{
+	long ret;
+	struct tee_ioctl_shm_alloc_data data;
+	struct tee_shm *shm;
+
+	if (copy_from_user(&data, udata, sizeof(data)))
+		return -EFAULT;
+
+	/* Currently no input flags are supported */
+	if (data.flags)
+		return -EINVAL;
+
+	data.fd = -1;
+
+	shm = tee_shm_alloc(ctx->teedev, data.size,
+			    TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+
+	data.flags = shm->flags;
+	data.size = shm->size;
+	data.fd = tee_shm_get_fd(shm);
+	if (data.fd < 0) {
+		ret = data.fd;
+		goto err;
+	}
+
+	if (copy_to_user(udata, &data, sizeof(data))) {
+		ret = -EFAULT;
+		goto err;
+	}
+	/*
+	 * When user space closes the file descriptor the shared memory
+	 * should be freed
+	 */
+	tee_shm_put(shm);
+	return 0;
+err:
+	if (data.fd >= 0)
+		tee_shm_put_fd(data.fd);
+	tee_shm_free(shm);
+	return ret;
+}
+
+static int params_from_user(struct tee_param *params, size_t num_params,
+		struct tee_ioctl_param __user *uparams)
+{
+	size_t n;
+
+	for (n = 0; n < num_params; n++) {
+		struct tee_shm *shm;
+		struct tee_ioctl_param ip;
+
+		if (copy_from_user(&ip, uparams + n, sizeof(ip)))
+			return -EFAULT;
+
+		/* All unused attribute bits has to be zero */
+		if (ip.attr & ~TEE_IOCTL_PARAM_ATTR_TYPE_MASK)
+			return -EINVAL;
+
+		params[n].attr = ip.attr;
+		switch (ip.attr) {
+		case TEE_IOCTL_PARAM_ATTR_TYPE_NONE:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
+			params[n].u.value.a = ip.u.value.a;
+			params[n].u.value.b = ip.u.value.b;
+			params[n].u.value.c = ip.u.value.c;
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
+			/*
+			 * If we fail to get a pointer to a shared memory
+			 * object (and increase the ref count) from a file
+			 * descriptor we return an error. All pointers that
+			 * has been added in params have an increased ref
+			 * count. It's the callers responibility to do
+			 * tee_shm_put() on all resolved pointers.
+			 */
+			shm = tee_shm_get_from_fd(ip.u.memref.shm_fd);
+			if (IS_ERR(shm))
+				return PTR_ERR(shm);
+
+			params[n].u.memref.shm_offs = ip.u.memref.shm_offs;
+			params[n].u.memref.size = ip.u.memref.size;
+			params[n].u.memref.shm = shm;
+			break;
+		default:
+			/* Unknown attribute */
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+static int params_to_user(struct tee_ioctl_param __user *uparams,
+		size_t num_params, struct tee_param *params)
+{
+	size_t n;
+
+	for (n = 0; n < num_params; n++) {
+		struct tee_ioctl_param __user *up = uparams + n;
+		struct tee_param *p = params + n;
+
+		switch (p->attr) {
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
+			if (put_user(p->u.value.a, &up->u.value.a) ||
+			    put_user(p->u.value.b, &up->u.value.b) ||
+			    put_user(p->u.value.c, &up->u.value.c))
+				return -EFAULT;
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
+			if (put_user((u64)p->u.memref.size, &up->u.memref.size))
+				return -EFAULT;
+		default:
+			break;
+		}
+	}
+	return 0;
+}
+
+static bool param_is_memref(struct tee_param *param)
+{
+	switch (param->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
+	case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
+	case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
+	case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static int tee_ioctl_open_session(struct tee_context *ctx,
+		struct tee_ioctl_buf_data __user *ubuf)
+{
+	int rc;
+	size_t n;
+	struct tee_ioctl_buf_data buf;
+	struct tee_ioctl_open_session_arg __user *uarg;
+	struct tee_ioctl_open_session_arg arg;
+	struct tee_ioctl_param __user *uparams = NULL;
+	struct tee_param *params = NULL;
+	bool have_session = false;
+
+	if (!ctx->teedev->desc->ops->open_session)
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, sizeof(buf)))
+		return -EFAULT;
+
+	if (buf.buf_len > TEE_MAX_ARG_SIZE ||
+	    buf.buf_len < sizeof(struct tee_ioctl_open_session_arg))
+		return -EINVAL;
+
+	uarg = (struct tee_ioctl_open_session_arg __user *)(unsigned long)
+		buf.buf_ptr;
+	rc = copy_from_user(&arg, uarg, sizeof(arg));
+	if (rc)
+		return rc;
+
+	if (sizeof(arg) + TEE_IOCTL_PARAM_SIZE(arg.num_params) != buf.buf_len)
+		return -EINVAL;
+
+	if (arg.num_params) {
+		params = kcalloc(arg.num_params, sizeof(struct tee_param),
+				GFP_KERNEL);
+		if (!params)
+			return -ENOMEM;
+		uparams = (struct tee_ioctl_param __user *)(uarg + 1);
+		rc = params_from_user(params, arg.num_params, uparams);
+		if (rc)
+			goto out;
+	}
+
+	rc = ctx->teedev->desc->ops->open_session(ctx, &arg, params);
+	if (rc)
+		goto out;
+	have_session = true;
+
+	if (put_user(arg.session, &uarg->session) ||
+	    put_user(arg.ret, &uarg->ret) ||
+	    put_user(arg.ret_origin, &uarg->ret_origin)) {
+		rc = -EFAULT;
+		goto out;
+	}
+	rc = params_to_user(uparams, arg.num_params, params);
+out:
+	/*
+	 * If we've succeeded to open the session but failed to communicate
+	 * it back to user space, close the session again to avoid leakage.
+	 */
+	if (rc && have_session && ctx->teedev->desc->ops->close_session)
+		ctx->teedev->desc->ops->close_session(ctx, arg.session);
+
+	if (params) {
+		/* Decrease ref count for all valid shared memory pointers */
+		for (n = 0; n < arg.num_params; n++)
+			if (param_is_memref(params + n) &&
+			    params[n].u.memref.shm)
+				tee_shm_put(params[n].u.memref.shm);
+		kfree(params);
+	}
+
+	return rc;
+}
+
+static int tee_ioctl_invoke(struct tee_context *ctx,
+		struct tee_ioctl_buf_data __user *ubuf)
+{
+	int rc;
+	size_t n;
+	struct tee_ioctl_buf_data buf;
+	struct tee_ioctl_invoke_arg __user *uarg;
+	struct tee_ioctl_invoke_arg arg;
+	struct tee_ioctl_param __user *uparams = NULL;
+	struct tee_param *params = NULL;
+
+	if (!ctx->teedev->desc->ops->invoke_func)
+		return -EINVAL;
+
+	rc = copy_from_user(&buf, ubuf, sizeof(buf));
+	if (rc)
+		return rc;
+
+	if (buf.buf_len > TEE_MAX_ARG_SIZE ||
+	    buf.buf_len < sizeof(struct tee_ioctl_invoke_arg))
+		return -EINVAL;
+
+	uarg = (struct tee_ioctl_invoke_arg __user *)(unsigned long)buf.buf_ptr;
+	if (copy_from_user(&arg, uarg, sizeof(arg)))
+		return -EFAULT;
+
+	if (sizeof(arg) + TEE_IOCTL_PARAM_SIZE(arg.num_params) != buf.buf_len)
+		return -EINVAL;
+
+	if (arg.num_params) {
+		params = kcalloc(arg.num_params, sizeof(struct tee_param),
+				GFP_KERNEL);
+		if (!params)
+			return -ENOMEM;
+		uparams = (struct tee_ioctl_param __user *)(uarg + 1);
+		rc = params_from_user(params, arg.num_params, uparams);
+		if (rc)
+			goto out;
+	}
+
+	rc = ctx->teedev->desc->ops->invoke_func(ctx, &arg, params);
+	if (rc)
+		goto out;
+
+	if (put_user(arg.ret, &uarg->ret) ||
+	    put_user(arg.ret_origin, &uarg->ret_origin)) {
+		rc = -EFAULT;
+		goto out;
+	}
+	rc = params_to_user(uparams, arg.num_params, params);
+out:
+	if (params) {
+		/* Decrease ref count for all valid shared memory pointers */
+		for (n = 0; n < arg.num_params; n++)
+			if (param_is_memref(params + n) &&
+			    params[n].u.memref.shm)
+				tee_shm_put(params[n].u.memref.shm);
+		kfree(params);
+	}
+	return rc;
+}
+
+
+static int tee_ioctl_cancel(struct tee_context *ctx,
+		struct tee_ioctl_cancel_arg __user *uarg)
+{
+	struct tee_ioctl_cancel_arg arg;
+
+	if (!ctx->teedev->desc->ops->cancel_req)
+		return -EINVAL;
+
+	if (copy_from_user(&arg, uarg, sizeof(arg)))
+		return -EFAULT;
+
+	return ctx->teedev->desc->ops->cancel_req(ctx, arg.cancel_id,
+						  arg.session);
+}
+
+static int tee_ioctl_close_session(struct tee_context *ctx,
+		struct tee_ioctl_close_session_arg __user *uarg)
+{
+	struct tee_ioctl_close_session_arg arg;
+
+	if (!ctx->teedev->desc->ops->close_session)
+		return -EINVAL;
+
+	if (copy_from_user(&arg, uarg, sizeof(arg)))
+		return -EFAULT;
+
+	return ctx->teedev->desc->ops->close_session(ctx, arg.session);
+}
+
+static int params_to_supp(struct tee_ioctl_param __user *uparams,
+		size_t num_params, struct tee_param *params)
+{
+	int rc = 0;
+	size_t n;
+	int *fds = kmalloc_array(num_params, sizeof(int), GFP_KERNEL);
+
+	if (!fds)
+		return -ENOMEM;
+	for (n = 0; n < num_params; n++)
+		fds[n] = -1;
+
+	for (n = 0; n < num_params; n++) {
+		struct tee_ioctl_param ip;
+		struct tee_param *p = params + n;
+
+		ip.attr = p->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK;
+		switch (p->attr) {
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
+			ip.u.value.a = p->u.value.a;
+			ip.u.value.b = p->u.value.b;
+			ip.u.value.c = p->u.value.c;
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
+			ip.u.memref.size = p->u.memref.size;
+			if (!p->u.memref.shm) {
+				ip.u.memref.shm_offs = 0;
+				ip.u.memref.shm_fd = -1;
+				break;
+			}
+			ip.u.memref.shm_offs = p->u.memref.shm_offs;
+			/*
+			 * This tee_shm_get_fd() is supposed to be matched
+			 * by a close(2) from tee-supplicant.
+			 */
+			fds[n] = tee_shm_get_fd(p->u.memref.shm);
+			if (fds[n] < 0) {
+				rc = fds[n];
+				goto out;
+			}
+			ip.u.memref.shm_fd = fds[n];
+			break;
+		default:
+			memset(&ip.u, 0, sizeof(ip.u));
+			break;
+		}
+
+		if (copy_to_user(uparams + n, &ip, sizeof(ip))) {
+			rc = -EFAULT;
+			goto out;
+		}
+	}
+out:
+	if (rc) {
+		for (n = 0; n < num_params; n++)
+			if (fds[n] >= 0)
+				tee_shm_put_fd(fds[n]);
+	}
+	kfree(fds);
+	return rc;
+}
+
+static int tee_ioctl_supp_recv(struct tee_context *ctx,
+		struct tee_ioctl_buf_data __user *ubuf)
+{
+	int rc;
+	struct tee_ioctl_buf_data buf;
+	struct tee_iocl_supp_recv_arg __user *uarg;
+	struct tee_param *params;
+	struct tee_ioctl_param __user *uparams;
+	u32 num_params;
+	u32 func;
+
+	if (!ctx->teedev->desc->ops->supp_recv)
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, sizeof(buf)))
+		return -EFAULT;
+
+	if (buf.buf_len > TEE_MAX_ARG_SIZE ||
+	    buf.buf_len < sizeof(struct tee_iocl_supp_recv_arg))
+		return -EINVAL;
+
+	uarg = (struct tee_iocl_supp_recv_arg __user *)(unsigned long)
+		buf.buf_ptr;
+	if (get_user(num_params, &uarg->num_params))
+		return -EFAULT;
+
+	if (sizeof(*uarg) + TEE_IOCTL_PARAM_SIZE(num_params) != buf.buf_len)
+		return -EINVAL;
+
+	params = kcalloc(num_params, sizeof(struct tee_param), GFP_KERNEL);
+	if (!params)
+		return -ENOMEM;
+
+	rc = ctx->teedev->desc->ops->supp_recv(ctx, &func, &num_params, params);
+	if (rc)
+		goto out;
+
+	if (put_user(func, &uarg->func) ||
+	    put_user(num_params, &uarg->num_params)) {
+		rc = -EFAULT;
+		goto out;
+	}
+
+	uparams = (struct tee_ioctl_param __user *)(uarg + 1);
+	rc = params_to_supp(uparams, num_params, params);
+out:
+	kfree(params);
+	return rc;
+}
+
+static int params_from_supp(struct tee_param *params,
+		size_t num_params, struct tee_ioctl_param __user *uparams)
+{
+	size_t n;
+
+	for (n = 0; n < num_params; n++) {
+		struct tee_param *p = params + n;
+		struct tee_ioctl_param ip;
+
+		if (copy_from_user(&ip, uparams + n, sizeof(ip)))
+			return -EFAULT;
+
+		/* All unused attribute bits has to be zero */
+		if (ip.attr & ~TEE_IOCTL_PARAM_ATTR_TYPE_MASK)
+			return -EINVAL;
+
+		p->attr = ip.attr;
+		switch (ip.attr) {
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
+			/* Only out and in/out values can be updated */
+			p->u.value.a = ip.u.value.a;
+			p->u.value.b = ip.u.value.b;
+			p->u.value.c = ip.u.value.c;
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
+			/*
+			 * Only the size of the memref can be updated.
+			 * Since we don't have access to the original
+			 * parameters here, only store the supplied size.
+			 * The driver will copy the updated size into the
+			 * original parameters.
+			 */
+			p->u.memref.shm = NULL;
+			p->u.memref.shm_offs = 0;
+			p->u.memref.size = ip.u.memref.size;
+			break;
+		default:
+			memset(&p->u, 0, sizeof(p->u));
+			break;
+		}
+	}
+	return 0;
+}
+
+static int tee_ioctl_supp_send(struct tee_context *ctx,
+		struct tee_ioctl_buf_data __user *ubuf)
+{
+	long rc;
+	struct tee_ioctl_buf_data buf;
+	struct tee_iocl_supp_send_arg __user *uarg;
+	struct tee_param *params;
+	struct tee_ioctl_param __user *uparams;
+	u32 num_params;
+	u32 ret;
+
+	/* Not valid for this driver */
+	if (!ctx->teedev->desc->ops->supp_send)
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, sizeof(buf)))
+		return -EFAULT;
+
+	if (buf.buf_len > TEE_MAX_ARG_SIZE ||
+	    buf.buf_len < sizeof(struct tee_iocl_supp_send_arg))
+		return -EINVAL;
+
+	uarg = (struct tee_iocl_supp_send_arg __user *)(unsigned long)
+		buf.buf_ptr;
+	if (get_user(ret, &uarg->ret) ||
+	    get_user(num_params, &uarg->num_params))
+		return -EFAULT;
+
+	if (sizeof(*uarg) + TEE_IOCTL_PARAM_SIZE(num_params) > buf.buf_len)
+		return -EINVAL;
+
+	params = kcalloc(num_params, sizeof(struct tee_param), GFP_KERNEL);
+	if (!params)
+		return -ENOMEM;
+
+	uparams = (struct tee_ioctl_param __user *)(uarg + 1);
+	rc = params_from_supp(params, num_params, uparams);
+	if (rc)
+		goto out;
+
+	rc = ctx->teedev->desc->ops->supp_send(ctx, ret, num_params, params);
+out:
+	kfree(params);
+	return rc;
+}
+
+
+static long tee_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct tee_context *ctx = filp->private_data;
+	void __user *uarg = (void __user *)arg;
+
+	switch (cmd) {
+	case TEE_IOC_VERSION:
+		return tee_ioctl_version(ctx, uarg);
+	case TEE_IOC_SHM_ALLOC:
+		return tee_ioctl_shm_alloc(ctx, uarg);
+	case TEE_IOC_OPEN_SESSION:
+		return tee_ioctl_open_session(ctx, uarg);
+	case TEE_IOC_INVOKE:
+		return tee_ioctl_invoke(ctx, uarg);
+	case TEE_IOC_CANCEL:
+		return tee_ioctl_cancel(ctx, uarg);
+	case TEE_IOC_CLOSE_SESSION:
+		return tee_ioctl_close_session(ctx, uarg);
+	case TEE_IOC_SUPPL_RECV:
+		return tee_ioctl_supp_recv(ctx, uarg);
+	case TEE_IOC_SUPPL_SEND:
+		return tee_ioctl_supp_send(ctx, uarg);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct file_operations tee_fops = {
+	.open = tee_open,
+	.release = tee_release,
+	.unlocked_ioctl = tee_ioctl,
+	.compat_ioctl = tee_ioctl,
+};
+
+static void tee_release_device(struct device *dev)
+{
+	struct tee_device *teedev = container_of(dev, struct tee_device, dev);
+
+	spin_lock(&driver_lock);
+	clear_bit(teedev->id, dev_mask);
+	spin_unlock(&driver_lock);
+	mutex_destroy(&teedev->mutex);
+	kfree(teedev);
+}
+
+struct tee_device *tee_device_alloc(const struct tee_desc *teedesc,
+			struct device *dev, struct tee_shm_pool *pool,
+			void *driver_data)
+{
+	struct tee_device *teedev;
+	void *ret;
+	int rc;
+	int offs = 0;
+
+	if (!teedesc || !teedesc->name || !teedesc->ops ||
+	    !teedesc->ops->get_version || !teedesc->ops->open ||
+	    !teedesc->ops->release || !dev || !pool)
+		return ERR_PTR(-EINVAL);
+
+	teedev = kzalloc(sizeof(*teedev), GFP_KERNEL);
+	if (!teedev) {
+		ret = ERR_PTR(-ENOMEM);
+		goto err;
+	}
+
+	if (teedesc->flags & TEE_DESC_PRIVILEGED)
+		offs = TEE_NUM_DEVICES / 2;
+
+	spin_lock(&driver_lock);
+	teedev->id = find_next_zero_bit(dev_mask, TEE_NUM_DEVICES, offs);
+	if (teedev->id < TEE_NUM_DEVICES)
+		set_bit(teedev->id, dev_mask);
+	spin_unlock(&driver_lock);
+
+	if (teedev->id >= TEE_NUM_DEVICES) {
+		ret = ERR_PTR(-ENOMEM);
+		goto err;
+	}
+
+	snprintf(teedev->name, sizeof(teedev->name), "tee%s%d",
+		 teedesc->flags & TEE_DESC_PRIVILEGED ? "priv" : "",
+		 teedev->id - offs);
+
+	teedev->dev.class = tee_class;
+	teedev->dev.release = tee_release_device;
+	teedev->dev.parent = dev;
+	teedev->dev.devt = MKDEV(MAJOR(tee_devt), teedev->id);
+
+	rc = dev_set_name(&teedev->dev, "%s", teedev->name);
+	if (rc) {
+		ret = ERR_PTR(rc);
+		goto err;
+	}
+
+	cdev_init(&teedev->cdev, &tee_fops);
+	teedev->cdev.owner = teedesc->owner;
+
+	dev_set_drvdata(&teedev->dev, driver_data);
+	device_initialize(&teedev->dev);
+
+	kref_init(&teedev->users);
+	init_completion(&teedev->c_no_users);
+	mutex_init(&teedev->mutex);
+	/* tee_device_unregister() does one final tee_device_put() */
+	tee_device_get(teedev);
+
+	teedev->desc = teedesc;
+	teedev->pool = pool;
+	INIT_LIST_HEAD(&teedev->list_shm);
+
+	return teedev;
+err:
+	dev_err(dev, "could not register %s driver\n",
+		teedesc->flags & TEE_DESC_PRIVILEGED ? "privileged" : "client");
+	if (teedev && teedev->id < TEE_NUM_DEVICES) {
+		spin_lock(&driver_lock);
+		clear_bit(teedev->id, dev_mask);
+		spin_unlock(&driver_lock);
+	}
+	kfree(teedev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tee_device_alloc);
+
+
+int tee_device_register(struct tee_device *teedev)
+{
+	int rc;
+
+	/*
+	 * If the teedev already is registered, don't do it again. It's
+	 * obviously an error to try to register twice, but if we return
+	 * an error we'll force the driver to remove the teedev.
+	 */
+	if (teedev->flags & TEE_DEVICE_FLAG_REGISTERED) {
+		dev_err(&teedev->dev, "attempt to register twice\n");
+		return 0;
+	}
+
+	rc = cdev_add(&teedev->cdev, teedev->dev.devt, 1);
+	if (rc) {
+		dev_err(&teedev->dev,
+			"unable to cdev_add() %s, major %d, minor %d, err=%d\n",
+			teedev->name, MAJOR(teedev->dev.devt),
+			MINOR(teedev->dev.devt), rc);
+		return rc;
+	}
+
+	rc = device_add(&teedev->dev);
+	if (rc) {
+		dev_err(&teedev->dev,
+			"unable to device_add() %s, major %d, minor %d, err=%d\n",
+			teedev->name, MAJOR(teedev->dev.devt),
+			MINOR(teedev->dev.devt), rc);
+		cdev_del(&teedev->cdev);
+		return rc;
+	}
+	teedev->flags |= TEE_DEVICE_FLAG_REGISTERED;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tee_device_register);
+
+static void tee_device_complete_unused(struct kref *kref)
+{
+	struct tee_device *teedev;
+
+	teedev = container_of(kref, struct tee_device, users);
+	/* When the mutex is released, no other tee_device_get() will succeed */
+	teedev->desc = NULL;
+	complete(&teedev->c_no_users);
+}
+
+void tee_device_put(struct tee_device *teedev)
+{
+	mutex_lock(&teedev->mutex);
+	/* Shouldn't put in this state */
+	if (!WARN_ON(!teedev->desc))
+		kref_put(&teedev->users, tee_device_complete_unused);
+	mutex_unlock(&teedev->mutex);
+}
+
+bool tee_device_get(struct tee_device *teedev)
+{
+	mutex_lock(&teedev->mutex);
+	if (!teedev->desc) {
+		mutex_unlock(&teedev->mutex);
+		return false;
+	}
+	kref_get(&teedev->users);
+	mutex_unlock(&teedev->mutex);
+	return true;
+}
+
+void tee_device_unregister(struct tee_device *teedev)
+{
+	if (IS_ERR_OR_NULL(teedev))
+		return;
+
+	if (teedev->flags & TEE_DEVICE_FLAG_REGISTERED) {
+		cdev_del(&teedev->cdev);
+		device_del(&teedev->dev);
+	}
+
+	tee_device_put(teedev);
+	wait_for_completion(&teedev->c_no_users);
+
+	/*
+	 * No need to take a mutex any longer now since teedev->desc was
+	 * set to NULL before teedev->c_no_users was completed.
+	 */
+
+	teedev->pool = NULL;
+
+	put_device(&teedev->dev);
+}
+EXPORT_SYMBOL_GPL(tee_device_unregister);
+
+void *tee_get_drvdata(struct tee_device *teedev)
+{
+	return dev_get_drvdata(&teedev->dev);
+}
+EXPORT_SYMBOL_GPL(tee_get_drvdata);
+
+static int __init tee_init(void)
+{
+	int rc;
+
+	tee_class = class_create(THIS_MODULE, "tee");
+	if (IS_ERR(tee_class)) {
+		pr_err("couldn't create class\n");
+		return PTR_ERR(tee_class);
+	}
+
+	rc = alloc_chrdev_region(&tee_devt, 0, TEE_NUM_DEVICES, "tee");
+	if (rc < 0) {
+		pr_err("failed to allocate char dev region\n");
+		class_destroy(tee_class);
+		tee_class = NULL;
+	}
+
+	return rc;
+}
+
+subsys_initcall(tee_init);
diff --git a/drivers/tee/tee_private.h b/drivers/tee/tee_private.h
new file mode 100644
index 0000000..4af5e46
--- /dev/null
+++ b/drivers/tee/tee_private.h
@@ -0,0 +1,80 @@ 
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#ifndef TEE_PRIVATE_H
+#define TEE_PRIVATE_H
+
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/completion.h>
+#include <linux/mutex.h>
+#include <linux/kref.h>
+
+struct tee_device;
+
+struct tee_shm {
+	struct list_head list_node;
+	struct tee_device *teedev;
+	phys_addr_t paddr;
+	void *kaddr;
+	size_t size;
+	struct dma_buf *dmabuf;
+	u32 flags;
+};
+
+struct tee_shm_pool_mgr;
+struct tee_shm_pool_mgr_ops {
+	int (*alloc)(struct tee_shm_pool_mgr *poolmgr, struct tee_shm *shm,
+		     size_t size);
+	void (*free)(struct tee_shm_pool_mgr *poolmgr, struct tee_shm *shm);
+};
+
+struct tee_shm_pool_mgr {
+	const struct tee_shm_pool_mgr_ops *ops;
+	void *private_data;
+};
+
+struct tee_shm_pool {
+	struct tee_shm_pool_mgr private_mgr;
+	struct tee_shm_pool_mgr dma_buf_mgr;
+	void (*destroy)(struct tee_shm_pool *pool);
+	void *private_data;
+};
+
+#define TEE_DEVICE_FLAG_REGISTERED	0x1
+#define TEE_MAX_DEV_NAME_LEN		32
+
+struct tee_device {
+	char name[TEE_MAX_DEV_NAME_LEN];
+	const struct tee_desc *desc;
+	int id;
+	unsigned flags;
+
+	struct device dev;
+	struct cdev cdev;
+
+	struct kref users;
+	struct completion c_no_users;
+	struct mutex mutex;
+
+	struct list_head list_shm;
+	struct tee_shm_pool *pool;
+};
+
+int tee_shm_init(void);
+
+bool tee_device_get(struct tee_device *teedev);
+void tee_device_put(struct tee_device *teedev);
+
+#endif /*TEE_PRIVATE_H*/
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
new file mode 100644
index 0000000..5296a45
--- /dev/null
+++ b/drivers/tee/tee_shm.c
@@ -0,0 +1,324 @@ 
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/device.h>
+#include <linux/fdtable.h>
+#include <linux/sched.h>
+#include <linux/dma-buf.h>
+#include <linux/slab.h>
+#include <linux/tee_drv.h>
+#include "tee_private.h"
+
+static void tee_shm_release(struct tee_shm *shm)
+{
+	struct tee_device *teedev = shm->teedev;
+	struct tee_shm_pool_mgr *poolm;
+
+	mutex_lock(&teedev->mutex);
+	list_del(&shm->list_node);
+	mutex_unlock(&teedev->mutex);
+
+	if (shm->flags & TEE_SHM_DMA_BUF)
+		poolm = &teedev->pool->dma_buf_mgr;
+	else
+		poolm = &teedev->pool->private_mgr;
+
+	poolm->ops->free(poolm, shm);
+	kfree(shm);
+
+	tee_device_put(teedev);
+}
+
+static struct sg_table *tee_shm_op_map_dma_buf(struct dma_buf_attachment
+			*attach, enum dma_data_direction dir)
+{
+	return NULL;
+}
+
+static void tee_shm_op_unmap_dma_buf(struct dma_buf_attachment *attach,
+			struct sg_table *table, enum dma_data_direction dir)
+{
+}
+
+static void tee_shm_op_release(struct dma_buf *dmabuf)
+{
+	struct tee_shm *shm = dmabuf->priv;
+
+	tee_shm_release(shm);
+}
+
+static void *tee_shm_op_kmap_atomic(struct dma_buf *dmabuf,
+			unsigned long pgnum)
+{
+	return NULL;
+}
+
+static void *tee_shm_op_kmap(struct dma_buf *dmabuf, unsigned long pgnum)
+{
+	return NULL;
+}
+
+static int tee_shm_op_mmap(struct dma_buf *dmabuf,
+			struct vm_area_struct *vma)
+{
+	struct tee_shm *shm = dmabuf->priv;
+	size_t size = vma->vm_end - vma->vm_start;
+
+	return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
+			       size, vma->vm_page_prot);
+}
+
+static struct dma_buf_ops tee_shm_dma_buf_ops = {
+	.map_dma_buf = tee_shm_op_map_dma_buf,
+	.unmap_dma_buf = tee_shm_op_unmap_dma_buf,
+	.release = tee_shm_op_release,
+	.kmap_atomic = tee_shm_op_kmap_atomic,
+	.kmap = tee_shm_op_kmap,
+	.mmap = tee_shm_op_mmap,
+};
+
+struct tee_shm *tee_shm_alloc(struct tee_device *teedev, size_t size,
+			u32 flags)
+{
+	struct tee_shm_pool_mgr *poolm = NULL;
+	struct tee_shm *shm;
+	void *ret;
+	int rc;
+
+	if (!(flags & TEE_SHM_MAPPED)) {
+		dev_err(teedev->dev.parent,
+			"only mapped allocations supported\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if ((flags & ~(TEE_SHM_MAPPED|TEE_SHM_DMA_BUF))) {
+		dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (!tee_device_get(teedev))
+		return ERR_PTR(-EINVAL);
+
+	if (!teedev->pool) {
+		/* teedev has been detached from driver */
+		ret = ERR_PTR(-EINVAL);
+		goto err;
+	}
+
+	shm = kzalloc(sizeof(struct tee_shm), GFP_KERNEL);
+	if (!shm) {
+		ret = ERR_PTR(-ENOMEM);
+		goto err;
+	}
+
+	shm->flags = flags;
+	shm->teedev = teedev;
+	if (flags & TEE_SHM_DMA_BUF)
+		poolm = &teedev->pool->dma_buf_mgr;
+	else
+		poolm = &teedev->pool->private_mgr;
+
+	rc = poolm->ops->alloc(poolm, shm, size);
+	if (rc) {
+		ret = ERR_PTR(rc);
+		goto err;
+	}
+
+	mutex_lock(&teedev->mutex);
+	list_add_tail(&shm->list_node, &teedev->list_shm);
+	mutex_unlock(&teedev->mutex);
+
+	if (flags & TEE_SHM_DMA_BUF) {
+		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+		exp_info.ops = &tee_shm_dma_buf_ops;
+		exp_info.size = shm->size;
+		exp_info.flags = O_RDWR;
+		exp_info.priv = shm;
+
+		shm->dmabuf = dma_buf_export(&exp_info);
+		if (IS_ERR(shm->dmabuf)) {
+			ret = ERR_CAST(shm->dmabuf);
+			goto err;
+		}
+	}
+
+	return shm;
+err:
+	if (poolm && shm && shm->kaddr)
+		poolm->ops->free(poolm, shm);
+	kfree(shm);
+	tee_device_put(teedev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tee_shm_alloc);
+
+int tee_shm_get_fd(struct tee_shm *shm)
+{
+	u32 req_flags = TEE_SHM_MAPPED | TEE_SHM_DMA_BUF;
+	int fd;
+
+	if ((shm->flags & req_flags) != req_flags)
+		return -EINVAL;
+
+	fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);
+	if (fd >= 0)
+		get_dma_buf(shm->dmabuf);
+	return fd;
+}
+EXPORT_SYMBOL_GPL(tee_shm_get_fd);
+
+int tee_shm_put_fd(int fd)
+{
+	return __close_fd(current->files, fd);
+}
+EXPORT_SYMBOL_GPL(tee_shm_put_fd);
+
+void tee_shm_free(struct tee_shm *shm)
+{
+
+	/*
+	 * dma_buf_put() decreases the dmabuf reference counter and will
+	 * call tee_shm_release() when the last reference is gone.
+	 *
+	 * In the case of anonymous memory we call tee_shm_release directly
+	 * instead at it doesn't have a reference counter.
+	 */
+	if (shm->flags & TEE_SHM_DMA_BUF)
+		dma_buf_put(shm->dmabuf);
+	else
+		tee_shm_release(shm);
+}
+EXPORT_SYMBOL_GPL(tee_shm_free);
+
+static bool cmp_key_va(struct tee_shm *shm, uintptr_t va)
+{
+	uintptr_t shm_va = (uintptr_t)shm->kaddr;
+
+	return (va >= shm_va) && (va < (shm_va + shm->size));
+}
+
+static bool cmp_key_pa(struct tee_shm *shm, uintptr_t pa)
+{
+	return (pa >= shm->paddr) && (pa < (shm->paddr + shm->size));
+}
+
+static struct tee_shm *tee_shm_find_by_key(struct tee_device *teedev, u32 flags,
+			bool (*cmp)(struct tee_shm *shm, uintptr_t key),
+			uintptr_t key)
+{
+	struct tee_shm *ret = NULL;
+	struct tee_shm *shm;
+
+	mutex_lock(&teedev->mutex);
+	list_for_each_entry(shm, &teedev->list_shm, list_node) {
+		if (cmp(shm, key)) {
+			ret = shm;
+			break;
+		}
+	}
+	mutex_unlock(&teedev->mutex);
+
+	return ret;
+}
+
+struct tee_shm *tee_shm_find_by_va(struct tee_device *teedev, u32 flags,
+			void *va)
+{
+	return tee_shm_find_by_key(teedev, flags, cmp_key_va, (uintptr_t)va);
+}
+EXPORT_SYMBOL_GPL(tee_shm_find_by_va);
+
+struct tee_shm *tee_shm_find_by_pa(struct tee_device *teedev, u32 flags,
+			phys_addr_t pa)
+{
+	return tee_shm_find_by_key(teedev, flags, cmp_key_pa, pa);
+}
+EXPORT_SYMBOL_GPL(tee_shm_find_by_pa);
+
+int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
+{
+	/* Check that we're in the range of the shm */
+	if ((char *)va < (char *)shm->kaddr)
+		return -EINVAL;
+	if ((char *)va >= ((char *)shm->kaddr + shm->size))
+		return -EINVAL;
+
+	return tee_shm_get_pa(
+			shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
+}
+EXPORT_SYMBOL_GPL(tee_shm_va2pa);
+
+int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
+{
+	/* Check that we're in the range of the shm */
+	if (pa < shm->paddr)
+		return -EINVAL;
+	if (pa >= (shm->paddr + shm->size))
+		return -EINVAL;
+
+	if (va) {
+		void *v = tee_shm_get_va(shm, pa - shm->paddr);
+
+		if (IS_ERR(v))
+			return PTR_ERR(v);
+		*va = v;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tee_shm_pa2va);
+
+void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
+{
+	if (offs >= shm->size)
+		return ERR_PTR(-EINVAL);
+	return (char *)shm->kaddr + offs;
+}
+EXPORT_SYMBOL_GPL(tee_shm_get_va);
+
+int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa)
+{
+	if (offs >= shm->size)
+		return -EINVAL;
+	if (pa)
+		*pa = shm->paddr + offs;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tee_shm_get_pa);
+
+static bool is_shm_dma_buf(struct dma_buf *dmabuf)
+{
+	return dmabuf->ops == &tee_shm_dma_buf_ops;
+}
+
+struct tee_shm *tee_shm_get_from_fd(int fd)
+{
+	struct dma_buf *dmabuf = dma_buf_get(fd);
+
+	if (IS_ERR(dmabuf))
+		return ERR_CAST(dmabuf);
+
+	if (!is_shm_dma_buf(dmabuf)) {
+		dma_buf_put(dmabuf);
+		return ERR_PTR(-EINVAL);
+	}
+	return dmabuf->priv;
+}
+EXPORT_SYMBOL_GPL(tee_shm_get_from_fd);
+
+void tee_shm_put(struct tee_shm *shm)
+{
+	if (shm->flags & TEE_SHM_DMA_BUF)
+		dma_buf_put(shm->dmabuf);
+}
+EXPORT_SYMBOL_GPL(tee_shm_put);
diff --git a/drivers/tee/tee_shm_pool.c b/drivers/tee/tee_shm_pool.c
new file mode 100644
index 0000000..2ef22bc
--- /dev/null
+++ b/drivers/tee/tee_shm_pool.c
@@ -0,0 +1,133 @@ 
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+#include <linux/slab.h>
+#include <linux/genalloc.h>
+#include <linux/tee_drv.h>
+#include "tee_private.h"
+
+static int pool_op_gen_alloc(struct tee_shm_pool_mgr *poolm,
+			struct tee_shm *shm, size_t size)
+{
+	unsigned long va;
+	struct gen_pool *genpool = poolm->private_data;
+	size_t s = roundup(size, 1 << genpool->min_alloc_order);
+
+	va = gen_pool_alloc(genpool, s);
+	if (!va)
+		return -ENOMEM;
+	shm->kaddr = (void *)va;
+	shm->paddr = gen_pool_virt_to_phys(genpool, va);
+	shm->size = s;
+	return 0;
+}
+
+static void pool_op_gen_free(struct tee_shm_pool_mgr *poolm,
+			struct tee_shm *shm)
+{
+	gen_pool_free(poolm->private_data, (unsigned long)shm->kaddr,
+		      shm->size);
+	shm->kaddr = NULL;
+}
+
+static const struct tee_shm_pool_mgr_ops pool_ops_generic = {
+	.alloc = pool_op_gen_alloc,
+	.free = pool_op_gen_free,
+};
+
+static void pool_res_mem_destroy(struct tee_shm_pool *pool)
+{
+	gen_pool_destroy(pool->private_mgr.private_data);
+	gen_pool_destroy(pool->dma_buf_mgr.private_data);
+}
+
+static int pool_res_mem_mgr_init(struct tee_shm_pool_mgr *mgr,
+			struct tee_shm_pool_mem_info *info, int min_alloc_order)
+{
+	size_t page_mask = PAGE_SIZE - 1;
+	struct gen_pool *genpool = NULL;
+	int rc;
+
+	/*
+	 * Start and end must be page aligned
+	 */
+	if ((info->vaddr & page_mask) || (info->paddr & page_mask) ||
+	    (info->size & page_mask))
+		return -EINVAL;
+
+	genpool = gen_pool_create(min_alloc_order, -1);
+	if (!genpool)
+		return -ENOMEM;
+
+	gen_pool_set_algo(genpool, gen_pool_best_fit, NULL);
+	rc = gen_pool_add_virt(genpool, info->vaddr, info->paddr, info->size,
+			       -1);
+	if (rc) {
+		gen_pool_destroy(genpool);
+		return rc;
+	}
+
+	mgr->private_data = genpool;
+	mgr->ops = &pool_ops_generic;
+	return 0;
+}
+
+struct tee_shm_pool *tee_shm_pool_alloc_res_mem(struct device *dev,
+			struct tee_shm_pool_mem_info *priv_info,
+			struct tee_shm_pool_mem_info *dmabuf_info)
+{
+	struct tee_shm_pool *pool = NULL;
+	int ret;
+
+	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
+	if (!pool) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	/*
+	 * Create the pool for driver private shared memory
+	 */
+	ret = pool_res_mem_mgr_init(&pool->private_mgr, priv_info,
+				    3 /* 8 byte aligned */);
+	if (ret)
+		goto err;
+
+	/*
+	 * Create the pool for dma_buf shared memory
+	 */
+	ret = pool_res_mem_mgr_init(&pool->dma_buf_mgr, dmabuf_info,
+				    PAGE_SHIFT);
+	if (ret)
+		goto err;
+
+	pool->destroy = pool_res_mem_destroy;
+	return pool;
+err:
+	if (ret == -ENOMEM)
+		dev_err(dev, "can't allocate memory for res_mem shared memory pool\n");
+	if (pool && pool->private_mgr.private_data)
+		gen_pool_destroy(pool->private_mgr.private_data);
+	kfree(pool);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(tee_shm_pool_alloc_res_mem);
+
+void tee_shm_pool_free(struct tee_shm_pool *pool)
+{
+	pool->destroy(pool);
+	kfree(pool);
+}
+EXPORT_SYMBOL_GPL(tee_shm_pool_free);
diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
new file mode 100644
index 0000000..6094173
--- /dev/null
+++ b/include/linux/tee_drv.h
@@ -0,0 +1,306 @@ 
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __TEE_DRV_H
+#define __TEE_DRV_H
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/tee.h>
+
+/*
+ * The file describes the API provided by the generic TEE driver to the
+ * specific TEE driver.
+ */
+
+#define TEE_SHM_MAPPED		0x1	/* Memory mapped by the kernel */
+#define TEE_SHM_DMA_BUF		0x2	/* Memory with dma-buf handle */
+
+struct tee_device;
+struct tee_shm;
+struct tee_shm_pool;
+
+/**
+ * struct tee_context - driver specific context on file pointer data
+ * @teedev:	pointer to this drivers struct tee_device
+ * @data:	driver specific context data, managed by the driver
+ */
+struct tee_context {
+	struct tee_device *teedev;
+	void *data;
+};
+
+struct tee_param_memref {
+	size_t shm_offs;
+	size_t size;
+	struct tee_shm *shm;
+};
+
+struct tee_param_value {
+	u64 a;
+	u64 b;
+	u64 c;
+};
+
+struct tee_param {
+	u64 attr;
+	union {
+		struct tee_param_memref memref;
+		struct tee_param_value value;
+	} u;
+};
+
+/**
+ * struct tee_driver_ops - driver operations vtable
+ * @get_version:	returns version of driver
+ * @open:		called when the device file is opened
+ * @release:		release this open file
+ */
+struct tee_driver_ops {
+	void (*get_version)(struct tee_context *ctx,
+			struct tee_ioctl_version_data *vers);
+	int (*open)(struct tee_context *ctx);
+	void (*release)(struct tee_context *ctx);
+	int (*open_session)(struct tee_context *ctx,
+			struct tee_ioctl_open_session_arg *arg,
+			struct tee_param *param);
+	int (*close_session)(struct tee_context *ctx, u32 session);
+	int (*invoke_func)(struct tee_context *ctx,
+			struct tee_ioctl_invoke_arg *arg,
+			struct tee_param *param);
+	int (*cancel_req)(struct tee_context *ctx, u32 cancel_id, u32 session);
+	int (*supp_recv)(struct tee_context *ctx, u32 *func, u32 *num_params,
+			struct tee_param *param);
+	int (*supp_send)(struct tee_context *ctx, u32 ret, u32 num_params,
+			struct tee_param *param);
+};
+
+/**
+ * struct tee_desc - Describes the TEE driver to the subsystem
+ * @name:	name of driver
+ * @ops:	driver operations vtable
+ * @owner:	module providing the driver
+ * @flags:	Extra properties of driver, defined by TEE_DESC_* below
+ */
+#define TEE_DESC_PRIVILEGED	0x1
+struct tee_desc {
+	const char *name;
+	const struct tee_driver_ops *ops;
+	struct module *owner;
+	u32 flags;
+};
+
+
+/**
+ * tee_device_alloc() - Allocate a new struct tee_device instance
+ * @teedesc:	Descriptor for this driver
+ * @dev:	Parent device for this device
+ * @pool:	Shared memory pool, NULL if not used
+ * @driver_data: Private driver data for this device
+ *
+ * Allocates a new struct tee_device instance. The device is
+ * removed by tee_device_unregister().
+ *
+ * @returns a pointer to a 'struct tee_device' or an ERR_PTR on failure
+ */
+struct tee_device *tee_device_alloc(const struct tee_desc *teedesc,
+			struct device *dev, struct tee_shm_pool *pool,
+			void *driver_data);
+
+/**
+ * tee_device_register() - Registers a TEE device
+ * @teedev:	Device to register
+ *
+ * tee_device_unregister() need to be called to remove the @teedev if
+ * this function fails.
+ *
+ * @returns < 0 on failure
+ */
+int tee_device_register(struct tee_device *teedev);
+
+/**
+ * tee_device_unregister() - Removes a TEE device
+ * @teedev:	Device to unregister
+ *
+ * This function should be called to remove the @teedev even if
+ * tee_device_register() hasn't been called yet. Does nothing if
+ * IS_ERR_OR_NULL(@teedev) is true.
+ */
+void tee_device_unregister(struct tee_device *teedev);
+
+/**
+ * struct tee_shm_pool_mem_info - holds information needed to create a shared memory pool
+ * @vaddr:	Virtual address of start of pool
+ * @paddr:	Physical address of start of pool
+ * @size:	Size in bytes of the pool
+ */
+struct tee_shm_pool_mem_info {
+	unsigned long vaddr;
+	unsigned long paddr;
+	size_t size;
+};
+
+/**
+ * tee_shm_pool_alloc_res_mem() - Create a shared memory pool from reserved memory range
+ * @dev:	Device allocating the pool
+ * @priv_info:	Information for driver private shared memory pool
+ * @dmabuf_info: Information for dma-buf shared memory pool
+ *
+ * Start and end of pools will must be page aligned.
+ *
+ * Allocation with the flag TEE_SHM_DMA_BUF set will use the range supplied
+ * in @dmabuf, others will use the range provided by @priv.
+ *
+ * @returns pointer to a 'struct tee_shm_pool' or an ERR_PTR on failure.
+ */
+struct tee_shm_pool *tee_shm_pool_alloc_res_mem(struct device *dev,
+			struct tee_shm_pool_mem_info *priv_info,
+			struct tee_shm_pool_mem_info *dmabuf_info);
+
+/**
+ * tee_shm_pool_free() - Free a shared memory pool
+ * @pool:	The shared memory pool to free
+ *
+ * The must be no remaining shared memory allocated from this pool when
+ * this function is called.
+ */
+void tee_shm_pool_free(struct tee_shm_pool *pool);
+
+/**
+ * tee_get_drvdata() - Return driver_data pointer
+ * @returns the driver_data pointer supplied to tee_register().
+ */
+void *tee_get_drvdata(struct tee_device *teedev);
+
+/**
+ * tee_shm_alloc() - Allocate shared memory
+ * @teedev:	Driver that allocates the shared memory
+ * @size:	Requested size of shared memory
+ * @flags:	Flags setting properties for the requested shared memory.
+ *
+ * Memory allocated as global shared memory is automatically freed when the
+ * TEE file pointer is closed. The @flags field uses the bits defined by
+ * TEE_SHM_* above. TEE_SHM_MAPPED must currently always be set. If
+ * TEE_SHM_DMA_BUF global shared memory will be allocated and associated
+ * with a dma-buf handle, else driver private memory.
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+struct tee_shm *tee_shm_alloc(struct tee_device *teedev, size_t size,
+			u32 flags);
+
+/**
+ * tee_shm_free() - Free shared memory
+ * @shm:	Handle to shared memory to free
+ */
+void tee_shm_free(struct tee_shm *shm);
+
+/**
+ * tee_shm_find_by_va() - Find a shared memory handle by a virtual address
+ * @teedev:	The device that owns the shared memory
+ * @flags:	Select which type of shared memory to locate, if
+ *		TEE_SHM_DMA_BUF global shared memory else driver private
+ *		shared memory.
+ * @va:		Virtual address covered by the shared memory
+ * @returns a Handle to shared memory
+ */
+struct tee_shm *tee_shm_find_by_va(struct tee_device *teedev, u32 flags,
+			void *va);
+/**
+ * tee_shm_find_by_pa() - Find a shared memory handle by a physical address
+ * @teedev:	The device that owns the shared memory
+ * @flags:	Select which type of shared memory to locate, if
+ *		TEE_SHM_DMA_BUF global shared memory else driver private
+ *		shared memory.
+ * @pa:		Physical address covered by the shared memory
+ * @returns a Handle to shared memory
+ */
+struct tee_shm *tee_shm_find_by_pa(struct tee_device *teedev, u32 flags,
+			phys_addr_t pa);
+
+/**
+ * tee_shm_va2pa() - Get physical address of a virtual address
+ * @shm:	Shared memory handle
+ * @va:		Virtual address to tranlsate
+ * @pa:		Returned physical address
+ * @returns 0 on success and < 0 on failure
+ */
+int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa);
+
+/**
+ * tee_shm_pa2va() - Get virtual address of a physical address
+ * @shm:	Shared memory handle
+ * @pa:		Physical address to tranlsate
+ * @va:		Returned virtual address
+ * @returns 0 on success and < 0 on failure
+ */
+int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va);
+
+/**
+ * tee_shm_get_size() - Get size of a shared memory
+ * @returns the size of the shared memory
+ */
+size_t tee_shm_get_size(struct tee_shm *shm);
+
+/**
+ * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
+ * @shm:	Shared memory handle
+ * @offs:	Offset from start of this shared memory
+ * @returns virtual address of the shared memory + offs if offs is within
+ *	the bounds of this shared memory, else an ERR_PTR
+ */
+void *tee_shm_get_va(struct tee_shm *shm, size_t offs);
+
+/**
+ * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
+ * @shm:	Shared memory handle
+ * @offs:	Offset from start of this shared memory
+ * @pa:		Physical address to return
+ * @returns 0 if offs is within the bounds of this shared memory, else an
+ *	error code.
+ */
+int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa);
+
+/**
+ * tee_shm_get_from_fd() - Get a shared memory handle from a file descriptor
+ * @fd:		A user space file descriptor
+ *
+ * This function increases the reference counter on the shared memory and
+ * returns a handle.
+ * @returns handle to shared memory
+ */
+struct tee_shm *tee_shm_get_from_fd(int fd);
+
+/**
+ * tee_shm_put() - Decrease reference count on a shared memory handle
+ * @shm:	Shared memory handle
+ */
+void tee_shm_put(struct tee_shm *shm);
+
+/**
+ * tee_shm_get_fd() - Increase reference count and return file descriptor
+ * @shm:	Shared memory handle
+ * @returns user space file descriptor to shared memory
+ */
+int tee_shm_get_fd(struct tee_shm *shm);
+
+/**
+ * tee_shm_put_fd() - Decrease reference count and close file descriptor
+ * @fd:		File descriptor to close
+ * @returns < 0 on failure
+ */
+int tee_shm_put_fd(int fd);
+
+#endif /*__TEE_DRV_H*/
diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h
new file mode 100644
index 0000000..39186c4
--- /dev/null
+++ b/include/uapi/linux/tee.h
@@ -0,0 +1,376 @@ 
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __TEE_H
+#define __TEE_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/*
+ * This file describes the API provided by a TEE driver to user space.
+ *
+ * Each TEE driver defines a TEE specific protocol which is used for the
+ * data passed back and forth using TEE_IOC_CMD.
+ */
+
+
+/* Helpers to make the ioctl defines */
+#define TEE_IOC_MAGIC	0xa4
+#define TEE_IOC_BASE	0
+
+/* Flags relating to shared memory */
+#define TEE_IOCTL_SHM_MAPPED	0x1	/* memory mapped in normal world */
+#define TEE_IOCTL_SHM_DMA_BUF	0x2	/* dma-buf handle on shared memory */
+
+#define TEE_MAX_ARG_SIZE	1024
+
+#define TEE_GEN_CAP_GP		(1 << 0)/* Global Platform compliant TEE */
+
+#define TEE_IMPL_ID_OPTEE	1
+#define TEE_OPTEE_CAP_TZ	(1 << 0)
+
+/**
+ * struct tee_version - TEE version
+ * @impl_id:	[out] TEE implementation id
+ * @impl_caps:	[out] Implementation specific capabilities
+ * @gen_caps:	[out] Generic capabilities, defined by TEE_GEN_CAPS_* above
+ *
+ * Identifies the TEE implementaion, @impl_id is one of TEE_IMPL_ID_* above.
+ * @impl_caps is implementation specific, for example TEE_OPTEE_CAP_*
+ * is valid when @impl_id == TEE_IMPL_ID_OPTEE.
+ */
+struct tee_ioctl_version_data {
+	__u32 impl_id;
+	__u32 impl_caps;
+	__u32 gen_caps;
+};
+/**
+ * TEE_IOC_VERSION - query version of TEE
+ *
+ * Takes a tee_version struct and returns with the TEE version data filled
+ * in.
+ */
+#define TEE_IOC_VERSION		_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 0, \
+				     struct tee_ioctl_version_data)
+
+/**
+ * struct tee_shm_alloc_data - Shared memory allocate argument
+ * @size:	[in/out] Size of shared memory to allocate
+ * @flags:	[in/out] Flags to/from allocation.
+ * @fd:		[out] dma_buf file descriptor of the shared memory
+ *
+ * The flags field should currently be zero as input. Updated by the call
+ * with actual flags as defined by TEE_IOCTL_SHM_* above.
+ * This structure is used as argument for TEE_IOC_SHM_ALLOC below.
+ */
+struct tee_ioctl_shm_alloc_data {
+	__u64 size;
+	__u32 flags;
+	__s32 fd;
+};
+/**
+ * TEE_IOC_SHM_ALLOC - allocate shared memory
+ *
+ * Allocates shared memory between the user space process and secure OS.
+ * The returned file descriptor is used to map the shared memory into user
+ * space. The shared memory is freed when the descriptor is closed and the
+ * memory is unmapped.
+ */
+#define TEE_IOC_SHM_ALLOC	_IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 1, \
+				     struct tee_ioctl_shm_alloc_data)
+
+/**
+ * struct tee_buf_data - Variable sized buffer
+ * @buf_ptr:	[in] A __user pointer to a buffer
+ * @buf_len:	[in] Length of the buffer above
+ *
+ * Used as argument for TEE_IOC_OPEN_SESSION, TEE_IOC_INVOKE,
+ * TEE_IOC_SUPPL_RECV, and TEE_IOC_SUPPL_SEND below.
+ */
+struct tee_ioctl_buf_data {
+	__u64 buf_ptr;
+	__u64 buf_len;
+};
+
+
+/*
+ * Attributes for struct tee_ioctl_param, selects field in the union
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_NONE		0	/* parameter not used */
+
+/*
+ * These defines value parameters (struct tee_ioctl_param_value)
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT	1
+#define TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT	2
+#define TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT	3	/* input and output */
+
+/*
+ * These defines shared memory reference parameters (struct
+ * tee_ioctl_param_memref)
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT	5
+#define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT	6
+#define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT	7	/* input and output */
+
+/*
+ * Mask for the type part of the attribute, leaves room for more types
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_MASK		0xff
+
+/*
+ * Matches TEEC_LOGIN_* in GP TEE Client API
+ * Is only defined for GP compliant TEEs
+ */
+#define TEE_IOCTL_LOGIN_PUBLIC			0
+#define TEE_IOCTL_LOGIN_USER			1
+#define TEE_IOCTL_LOGIN_GROUP			2
+#define TEE_IOCTL_LOGIN_APPLICATION		4
+#define TEE_IOCTL_LOGIN_USER_APPLICATION	5
+#define TEE_IOCTL_LOGIN_GROUP_APPLICATION	6
+
+/**
+ * struct tee_ioctl_param_memref - memory reference
+ * @shm_offs:	Offset into the shared memory object
+ * @size:	Size of the buffer
+ * @shm_fd:	Shared memory file descriptor
+ *
+ * Shared memory is allocated with TEE_IOC_SHM_ALLOC which returns a file
+ * descriptor connected to the shared memory object. A memref can reference
+ * a part of a shared memory by specifying an offset (@shm_offs) and @size
+ * of the object. To supply the entire shared memory object set @shm_offs to 0
+ * and @size to the previously returned size of the object.
+ */
+struct tee_ioctl_param_memref {
+	__u64 shm_offs;
+	__u64 size;
+	__s64 shm_fd;
+};
+
+/**
+ * struct tee_ioctl_param_value - values
+ * @a: first value
+ * @b: second value
+ * @c: third value
+ */
+struct tee_ioctl_param_value {
+	__u64 a;
+	__u64 b;
+	__u64 c;
+};
+
+/**
+ * struct tee_ioctl_param - parameter
+ * @attr: attributes
+ * @memref: a memory reference
+ * @value: a value
+ *
+ * @attr & TEE_PARAM_ATTR_TYPE_MASK indicates if memref or value is used in
+ * the union. TEE_PARAM_ATTR_TYPE_VALUE_* indicates value and
+ * TEE_PARAM_ATTR_TYPE_MEMREF_* indicates memref. TEE_PARAM_ATTR_TYPE_NONE
+ * indicates that none of the members are used.
+ */
+struct tee_ioctl_param {
+	__u64 attr;
+	union {
+		struct tee_ioctl_param_memref memref;
+		struct tee_ioctl_param_value value;
+	} u;
+};
+
+#define TEE_IOCTL_UUID_LEN		16
+
+/**
+ * struct tee_open_session_arg - Open session argument
+ * @uuid:	[in] UUID of the Trusted Application
+ * @clnt_uuid:	[in] UUID of client
+ * @clnt_login:	[in] Login class of client, TEE_LOGIN_* above
+ * @cancel_id:	[in] Cancellation id, a unique value to identify this request
+ * @session:	[out] Session id
+ * @ret:	[out] return value
+ * @ret_origin	[out] origin of the return value
+ * @num_params	[in] number of parameters following this struct
+ */
+struct tee_ioctl_open_session_arg {
+	__u8 uuid[TEE_IOCTL_UUID_LEN];
+	__u8 clnt_uuid[TEE_IOCTL_UUID_LEN];
+	__u32 clnt_login;
+	__u32 cancel_id;
+	__u32 session;
+	__u32 ret;
+	__u32 ret_origin;
+	__u32 num_params;
+	/*
+	 * this struct is 8 byte aligned since the 'struct tee_ioctl_param'
+	 * which follows requires 8 byte alignment.
+	 *
+	 * Commented out element used to visualize the layout dynamic part
+	 * of the struct. This field is not available at all if
+	 * num_params == 0.
+	 *
+	 * struct tee_ioctl_param params[num_params];
+	 */
+} __aligned(8);
+
+/**
+ * TEE_IOC_OPEN_SESSION - opens a session to a Trusted Application
+ *
+ * Takes a struct tee_ioctl_buf_data which contains a struct
+ * tee_ioctl_open_session_arg followed by any array of struct
+ * tee_ioctl_param
+ */
+#define TEE_IOC_OPEN_SESSION	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 2, \
+				     struct tee_ioctl_buf_data)
+
+/**
+ * struct tee_invoke_func_arg - Invokes a function in a Trusted Application
+ * @func:	[in] Trusted Application function, specific to the TA
+ * @session:	[in] Session id
+ * @cancel_id:	[in] Cancellation id, a unique value to identify this request
+ * @ret:	[out] return value
+ * @ret_origin	[out] origin of the return value
+ * @num_params	[in] number of parameters following this struct
+ */
+struct tee_ioctl_invoke_arg {
+	__u32 func;
+	__u32 session;
+	__u32 cancel_id;
+	__u32 ret;
+	__u32 ret_origin;
+	__u32 num_params;
+	/*
+	 * this struct is 8 byte aligned since the 'struct tee_ioctl_param'
+	 * which follows requires 8 byte alignment.
+	 *
+	 * Commented out element used to visualize the layout dynamic part
+	 * of the struct. This field is not available at all if
+	 * num_params == 0.
+	 *
+	 * struct tee_ioctl_param params[num_params];
+	 */
+} __aligned(8);
+
+/**
+ * TEE_IOC_INVOKE - Invokes a function in a Trusted Application
+ *
+ * Takes a struct tee_ioctl_buf_data which contains a struct
+ * tee_invoke_func_arg followed by any array of struct tee_param
+ */
+#define TEE_IOC_INVOKE		_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 3, \
+				     struct tee_ioctl_buf_data)
+
+/**
+ * struct tee_ioctl_cancel_arg - Cancels an open session or invoke ioctl
+ * @cancel_id:	[in] Cancellation id, a unique value to identify this request
+ * @session:	[in] Session id, if the session is opened, else set to 0
+ */
+struct tee_ioctl_cancel_arg {
+	__u32 cancel_id;
+	__u32 session;
+};
+/**
+ * TEE_IOC_CANCEL - Cancels an open session or invoke
+ */
+#define TEE_IOC_CANCEL		_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 4, \
+				     struct tee_ioctl_cancel_arg)
+
+/**
+ * struct tee_ioctl_close_session_arg - Closes an open session
+ * @session:	[in] Session id
+ */
+struct tee_ioctl_close_session_arg {
+	__u32 session;
+};
+/**
+ * TEE_IOC_CLOSE_SESSION - Closes a session
+ */
+#define TEE_IOC_CLOSE_SESSION	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 5, \
+				     struct tee_ioctl_close_session_arg)
+
+/**
+ * struct tee_iocl_supp_recv_arg - Receive a request for a supplicant function
+ * @func:	[in] supplicant function
+ * @num_params	[in/out] number of parameters following this struct
+ *
+ * @num_params is the number of params that tee-supplicant has room to
+ * receive when input, @num_params is the number of actual params
+ * tee-supplicant receives when output.
+ */
+struct tee_iocl_supp_recv_arg {
+	__u32 func;
+	__u32 num_params;
+	/*
+	 * this struct is 8 byte aligned since the 'struct tee_ioctl_param'
+	 * which follows requires 8 byte alignment.
+	 *
+	 * Commented out element used to visualize the layout dynamic part
+	 * of the struct. This field is not available at all if
+	 * num_params == 0.
+	 *
+	 * struct tee_ioctl_param params[num_params];
+	 */
+} __aligned(8);
+/**
+ * TEE_IOC_SUPPL_RECV - Receive a request for a supplicant function
+ *
+ * Takes a struct tee_ioctl_buf_data which contains a struct
+ * tee_iocl_supp_recv_arg followed by any array of struct tee_param
+ */
+#define TEE_IOC_SUPPL_RECV	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 6, \
+				     struct tee_ioctl_buf_data)
+
+
+/**
+ * struct tee_iocl_supp_send_arg - Send a response to a received request
+ * @ret:	[out] return value
+ * @num_params	[in] number of parameters following this struct
+ */
+struct tee_iocl_supp_send_arg {
+	__u32 ret;
+	__u32 num_params;
+	/*
+	 * this struct is 8 byte aligned since the 'struct tee_ioctl_param'
+	 * which follows requires 8 byte alignment.
+	 *
+	 * Commented out element used to visualize the layout dynamic part
+	 * of the struct. This field is not available at all if
+	 * num_params == 0.
+	 *
+	 * struct tee_ioctl_param params[num_params];
+	 */
+} __aligned(8);
+/**
+ * TEE_IOC_SUPPL_SEND - Receive a request for a supplicant function
+ *
+ * Takes a struct tee_ioctl_buf_data which contains a struct
+ * tee_iocl_supp_send_arg followed by any array of struct tee_param
+ */
+#define TEE_IOC_SUPPL_SEND	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 7, \
+				     struct tee_ioctl_buf_data)
+
+
+/*
+ * Five syscalls are used when communicating with the TEE driver.
+ * open(): opens the device associated with the driver
+ * ioctl(): as described above operating on the file descriptor from open()
+ * close(): two cases
+ *   - closes the device file descriptor
+ *   - closes a file descriptor connected to allocated shared memory
+ * mmap(): maps shared memory into user space using information from struct
+ *	   tee_ioctl_shm_alloc_data
+ * munmap(): unmaps previously shared memory
+ */
+
+#endif /*__TEE_H*/