Normal World can change contents of shared memory at any time.
Right now it does not pose any threat. But next patches
will rely on attribute values. Thus, we need to read
parameter attributes only once and then use this saved value.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>

Normal world now can call OPTEE_MSG_CMD_REGISTER_SHM and
OPTEE_MSG_CMD_UNREGISTER_SHM functions to register/unregister
shared memory.

After that, it can use OPTEE_MSG_ATTR_TYPE_RMEM_* to reference
to that registered shared buffers.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>

Now, when we can pass list of pages between REE and TEE it is possible
to use temporary memory references that are not located in a preallocated
shared memory area. By employing OPTEE_MSG_ATTR_NONCONTIG parameter
attribute, REE can provide own buffer as a temporary memory reference.

Actually, such parameters are indistinguishable from registered shared
memory references. So, when OP-TEE spots temporary memory reference with
OPTEE_MSG_ATTR_NONCONTIG attribute, it will create `mobj_reg_shm` for it.
After call was handled, it will free that mobj.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (HiKey)
Tested-by: Jens Wiklander <jens.wiklander@linaro.org> (FVP, QEMU v7/v8)
Tested-by: Jens Wiklander <jens.wiklander@linaro.org> (Juno with and without pager)
Tested-by: Volodymyr Babchuk <vlad.babchuk@gmail.com> (Rcar M3)

 - removed spaces before "?" in comments
 - Capitalized first letter in first words

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>

This variable can disable reported capability
OPTEE_SMC_SEC_CAP_DYNAMIC_SHM.

But dynamic SHM remains fully operational, though. This can be used
for testing and debugging to emulate system, where dynamic SHM is not
supported.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Acked-by: Jerome Forissier <jerome.forissier@linaro.org>