Reenable kernel login method for kernel TEE client API

The kernel TEE login method was accidentally disabled previously when
enabling a few other login methods, so fix that here.

* tag 'tee-fix-for-v5.10' of git://git.linaro.org:/people/jens.wiklander/linux-tee:
  tee: client UUID: Skip REE kernel login method as well

Link: https://lore.kernel.org/r/20201013070918.GA3328976@jade
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Since the addition of session's client UUID generation via commit [1],
login via REE kernel method was disallowed. So fix that via passing
nill UUID in case of TEE_IOCTL_LOGIN_REE_KERNEL method as well.

Fixes: e33bcbab16d1 ("tee: add support for session's client UUID generation") [1]
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

Simplify tee_device_register() and friends

Uses cdev_device_add() instead of the cdev_add() device_add()
combination.

Initializes dev->groups instead of direct calls to sysfs_create_group()
and friends.

* tag 'tee-dev-cleanup-for-v5.10' of git://git.linaro.org:/people/jens.wiklander/linux-tee:
  tee: avoid explicit sysfs_create/delete_group by initialising dev->groups
  tee: replace cdev_add + device_add with cdev_device_add

Link: https://lore.kernel.org/r/20200918144130.GB1219771@jade
Signed-off-by: Olof Johansson <olof@lixom.net>

If the dev->groups is initialised, the sysfs group is created as part
of device_add call. There is no need to call sysfs_create/delete_group
explicitly.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

Commit 233ed09d7fda ("chardev: add helper function to register char devs
with a struct device") added a helper function 'cdev_device_add'.

Make use of cdev_device_add in tee_device_register to replace cdev_add
and device_add. Since cdev_device_add takes care of setting the
kobj->parent, drop explicit initialisation in tee_device_alloc.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

Make sure I2C functions used in OP-TEE are reachable with IS_REACHABLE()

* tag 'optee-i2c-fix-for-v5.10' of git://git.linaro.org:/people/jens.wiklander/linux-tee:
  drivers: optee: fix i2c build issue

Link: https://lore.kernel.org/r/20200901101806.GA3286324@jade
Signed-off-by: Olof Johansson <olof@lixom.net>

When the optee driver is compiled into the kernel while the i2c core
is configured as a module, the i2c symbols are not available.

This commit addresses the situation by disabling the i2c support for
this use case while allowing it in all other scenarios:

 i2c=y, optee=y
 i2c=m, optee=m
 i2c=y, optee=m
 i2c=m, optee=y (not supported)

Fixes: c05210ab9757 ("drivers: optee: allow op-tee to access devices on the i2c bus")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

Converts tee subsystem to use pin_user_pages() instead of get_user_pages()

* tag 'tee-pin-user-pages-for-5.10' of git://git.linaro.org/people/jens.wiklander/linux-tee:
  tee: convert get_user_pages() --> pin_user_pages()

Link: https://lore.kernel.org/r/20200825090715.GA2370775@jade
Signed-off-by: Olof Johansson <olof@lixom.net>

This code was using get_user_pages*(), in a "Case 2" scenario
(DMA/RDMA), using the categorization from [1]. That means that it's
time to convert the get_user_pages*() + put_page() calls to
pin_user_pages*() + unpin_user_pages() calls.

Factor out a new, small release_registered_pages() function, in
order to consolidate the logic for discerning between
TEE_SHM_USER_MAPPED and TEE_SHM_KERNEL_MAPPED pages. This also
absorbs the kfree() call that is also required there.

There is some helpful background in [2]: basically, this is a small
part of fixing a long-standing disconnect between pinning pages, and
file systems' use of those pages.

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
    https://lwn.net/Articles/807108/

Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: tee-dev@lists.linaro.org
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

Handle NULL pointer indication from tee client

Adds support to indicate NULL pointers instead of a valid buffer when
querying the needed size of a buffer.

* tag 'tee-memref-null-for-v5.10' of git://git.linaro.org/people/jens.wiklander/linux-tee:
  driver: tee: Handle NULL pointer indication from client

Link: https://lore.kernel.org/r/20200821102535.GA1872111@jade
Signed-off-by: Olof Johansson <olof@lixom.net>