Commit graph

7 commits

Author SHA1 Message Date
Arnd Bergmann bad19e0d04 This pull request enables dynamic shared memory support in the TEE
subsystem as a whole and in OP-TEE in particular.
 
 Global Platform TEE specification [1] allows client applications
 to register part of own memory as a shared buffer between
 application and TEE. This allows fast zero-copy communication between
 TEE and REE. But current implementation of TEE in Linux does not support
 this feature.
 
 Also, current implementation of OP-TEE transport uses fixed size
 pre-shared buffer for all communications with OP-TEE OS. This is okay
 in the most use cases. But this prevents use of OP-TEE in virtualized
 environments, because:
  a) We can't share the same buffer between different virtual machines
  b) Physically contiguous memory as seen by VM can be non-contiguous
     in reality (and as seen by OP-TEE OS) due to second stage of
     MMU translation.
  c) Size of this pre-shared buffer is limited.
 
 So, first part of this pull request adds generic register/unregister
 interface to tee subsystem. The second part adds necessary features into
 OP-TEE driver, so it can use not only static pre-shared buffer, but
 whole RAM to communicate with OP-TEE OS.
 
 This change is backwards compatible allowing older secure world or
 user space to work with newer kernels and vice versa.
 
 [1] https://www.globalplatform.org/specificationsdevice.asp
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Merge tag 'tee-drv-dynamic-shm-for-v4.16' of https://git.linaro.org/people/jens.wiklander/linux-tee into next/drivers

Pull "tee dynamic shm for v4.16" from Jens Wiklander:

This pull request enables dynamic shared memory support in the TEE
subsystem as a whole and in OP-TEE in particular.

Global Platform TEE specification [1] allows client applications
to register part of own memory as a shared buffer between
application and TEE. This allows fast zero-copy communication between
TEE and REE. But current implementation of TEE in Linux does not support
this feature.

Also, current implementation of OP-TEE transport uses fixed size
pre-shared buffer for all communications with OP-TEE OS. This is okay
in the most use cases. But this prevents use of OP-TEE in virtualized
environments, because:
 a) We can't share the same buffer between different virtual machines
 b) Physically contiguous memory as seen by VM can be non-contiguous
    in reality (and as seen by OP-TEE OS) due to second stage of
    MMU translation.
 c) Size of this pre-shared buffer is limited.

So, first part of this pull request adds generic register/unregister
interface to tee subsystem. The second part adds necessary features into
OP-TEE driver, so it can use not only static pre-shared buffer, but
whole RAM to communicate with OP-TEE OS.

This change is backwards compatible allowing older secure world or
user space to work with newer kernels and vice versa.

[1] https://www.globalplatform.org/specificationsdevice.asp

* tag 'tee-drv-dynamic-shm-for-v4.16' of https://git.linaro.org/people/jens.wiklander/linux-tee:
  tee: shm: inline tee_shm_get_id()
  tee: use reference counting for tee_context
  tee: optee: enable dynamic SHM support
  tee: optee: add optee-specific shared pool implementation
  tee: optee: store OP-TEE capabilities in private data
  tee: optee: add registered buffers handling into RPC calls
  tee: optee: add registered shared parameters handling
  tee: optee: add shared buffer registration functions
  tee: optee: add page list manipulation functions
  tee: optee: Update protocol definitions
  tee: shm: add page accessor functions
  tee: shm: add accessors for buffer size and page offset
  tee: add register user memory
  tee: flexible shared memory pool creation
2017-12-21 17:23:52 +01:00
Volodymyr Babchuk 217e0250cc tee: use reference counting for tee_context
We need to ensure that tee_context is present until last
shared buffer will be freed.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
2017-12-15 13:36:18 +01:00
Jens Wiklander 033ddf12bc tee: add register user memory
Added new ioctl to allow users register own buffers as a shared memory.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
[jw: moved tee_shm_is_registered() declaration]
[jw: added space after __tee_shm_alloc() implementation]
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
2017-12-15 13:32:20 +01:00
Jens Wiklander f2aa97240c tee: add TEE_IOCTL_PARAM_ATTR_META
Adds TEE_IOCTL_PARAM_ATTR_META which can be used to indicate meta
parameters when communicating with user space. These meta parameters can
be used by supplicant support multiple parallel requests at a time.

Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
2017-11-29 10:37:13 +01:00
Jens Wiklander 84debcc535 tee: add tee_param_is_memref() for driver use
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
2017-11-29 10:37:13 +01:00
Jens Wiklander 059cf566e1 tee: indicate privileged dev in gen_caps
Mirrors the TEE_DESC_PRIVILEGED bit of struct tee_desc:flags into struct
tee_ioctl_version_data:gen_caps as TEE_GEN_CAP_PRIVILEGED in
tee_ioctl_version()

Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
2017-08-04 10:30:27 +02:00
Jens Wiklander 967c9cca2c tee: generic TEE subsystem
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.
* Sysfs implementation_id of TEE driver

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>

Acked-by: Andreas Dannenberg <dannenberg@ti.com>
Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (HiKey)
Tested-by: Volodymyr Babchuk <vlad.babchuk@gmail.com> (RCAR H3)
Tested-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
2017-03-09 15:42:33 +01:00