Hi Sumit,
On Mon, May 27, 2024 at 4:38 PM Sumit Garg <sumit.garg@xxxxxxxxxx> wrote:
>
> On Mon, 27 May 2024 at 17:44, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
> >
> > Adds support in the OP-TEE drivers (both SMC and FF-A ABIs) to probe and
> > use an RPMB device via the RPMB subsystem instead of passing the RPMB
> > frames via tee-supplicant in user space. A fallback mechanism is kept to
> > route RPMB frames via tee-supplicant if the RPMB subsystem isn't
> > available.
> >
> > The OP-TEE RPC ABI is extended to support iterating over all RPMB
> > devices until one is found with the expected RPMB key already
> > programmed.
> >
> > Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > Tested-by: Manuel Traut <manut@xxxxxxxxx>
> > ---
> > Documentation/ABI/testing/sysfs-class-tee | 15 ++
> > MAINTAINERS | 1 +
> > drivers/tee/optee/core.c | 96 +++++++++++-
> > drivers/tee/optee/device.c | 7 +
> > drivers/tee/optee/ffa_abi.c | 14 ++
> > drivers/tee/optee/optee_ffa.h | 2 +
> > drivers/tee/optee/optee_private.h | 26 +++-
> > drivers/tee/optee/optee_rpc_cmd.h | 35 +++++
> > drivers/tee/optee/optee_smc.h | 2 +
> > drivers/tee/optee/rpc.c | 177 ++++++++++++++++++++++
> > drivers/tee/optee/smc_abi.c | 14 ++
> > 11 files changed, 387 insertions(+), 2 deletions(-)
> > create mode 100644 Documentation/ABI/testing/sysfs-class-tee
> >
> > diff --git a/Documentation/ABI/testing/sysfs-class-tee b/Documentation/ABI/testing/sysfs-class-tee
> > new file mode 100644
> > index 000000000000..c9144d16003e
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-class-tee
> > @@ -0,0 +1,15 @@
> > +What: /sys/class/tee/tee{,priv}X/rpmb_routing_model
> > +Date: May 2024
> > +KernelVersion: 6.10
> > +Contact: op-tee@xxxxxxxxxxxxxxxxxxxxxxxxx
> > +Description:
> > + RPMB frames can be routed to the RPMB device via the
> > + user-space daemon tee-supplicant or the RPMB subsystem
> > + in the kernel. The value "user" means that the driver
> > + will route the RPMB frames via user space. Conversely,
> > + "kernel" means that the frames are routed via the RPMB
> > + subsystem without assistance from tee-supplicant. It
> > + should be assumed that RPMB frames are routed via user
> > + space if the variable is absent. The primary purpose
> > + of this variable is to let systemd know whether
> > + tee-supplicant is needed in the early boot with initramfs.
>
> Why do we need this if we already have [1] [2]? AFAICS, whichever
> devices like fTPM etc. systemd depends upon, it can be easily known
> via existing sysfs property.
>
> [1] https://docs.kernel.org/admin-guide/abi-testing.html?highlight=optee#abi-sys-bus-tee-devices-optee-ta-uuid-need-supplicant
> [2] Documentation/ABI/testing/sysfs-bus-optee-devices
The dependency is reversed. A TA depending on tee-supplicant will not
be loaded until tee-supplicant is ready. rpmb_routing_model is used as
one of the inputs to determine if tee-supplicant must be started early
or if it can wait until the real rootfs is available.
Thanks,
Jens
