| Message ID | 20210818101849.602257-2-jens.wiklander@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Asynchronous notifications from secure world | expand |
On Wed, 18 Aug 2021 11:18:44 +0100, Jens Wiklander <jens.wiklander@linaro.org> wrote: > > Adds a section on notifications used by OP-TEE, synchronous and > asynchronous. > > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> > --- > Documentation/staging/tee.rst | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/Documentation/staging/tee.rst b/Documentation/staging/tee.rst > index 4d4b5f889603..951f07dd026b 100644 > --- a/Documentation/staging/tee.rst > +++ b/Documentation/staging/tee.rst > @@ -184,6 +184,35 @@ order to support device enumeration. In other words, OP-TEE driver invokes this > application to retrieve a list of Trusted Applications which can be registered > as devices on the TEE bus. > > +OP-TEE notifications > +-------------------- > + > +There are two kinds of notifications that secure world can use to make > +normal world aware of some event. > + > +1. Synchronous notifications delivered with ``OPTEE_RPC_CMD_NOTIFICATION`` > + using the ``OPTEE_RPC_NOTIFICATION_SEND`` parameter. > +2. Asynchronous notifications delivered with a combination of a non-secure > + edge-triggered interrupt and a fast call from the non-secure interrupt > + handler. > + > +Synchronous notifications are limited by depending on RPC for delivery, > +this is only usable when secure world is entered with a yielding call via > +``OPTEE_SMC_CALL_WITH_ARG``. This excludes such notifications from secure > +world interrupt handlers. > + > +An asynchronous notification is delivered via a non-secure edge-triggered > +interrupt to an interrupt handler registered in the OP-TEE driver. The > +actual notification value are retrieved with the fast call > +``OPTEE_SMC_GET_ASYNC_NOTIF_VALUE``. One thing you may want to describe whether a single interrupt can represent multiple notification (multiple edge interrupts will happily be coalesced into a single one if not acknowledged before the next notification). Otherwise, Acked-by: Marc Zyngier <maz@kernel.org> M.
diff --git a/Documentation/staging/tee.rst b/Documentation/staging/tee.rst index 4d4b5f889603..951f07dd026b 100644 --- a/Documentation/staging/tee.rst +++ b/Documentation/staging/tee.rst @@ -184,6 +184,35 @@ order to support device enumeration. In other words, OP-TEE driver invokes this application to retrieve a list of Trusted Applications which can be registered as devices on the TEE bus. +OP-TEE notifications +-------------------- + +There are two kinds of notifications that secure world can use to make +normal world aware of some event. + +1. Synchronous notifications delivered with ``OPTEE_RPC_CMD_NOTIFICATION`` + using the ``OPTEE_RPC_NOTIFICATION_SEND`` parameter. +2. Asynchronous notifications delivered with a combination of a non-secure + edge-triggered interrupt and a fast call from the non-secure interrupt + handler. + +Synchronous notifications are limited by depending on RPC for delivery, +this is only usable when secure world is entered with a yielding call via +``OPTEE_SMC_CALL_WITH_ARG``. This excludes such notifications from secure +world interrupt handlers. + +An asynchronous notification is delivered via a non-secure edge-triggered +interrupt to an interrupt handler registered in the OP-TEE driver. The +actual notification value are retrieved with the fast call +``OPTEE_SMC_GET_ASYNC_NOTIF_VALUE``. + +One notification value ``OPTEE_SMC_ASYNC_NOTIF_VALUE_DO_BOTTOM_HALF`` has a +special meaning. When this value is received it means that normal world is +supposed to make a yielding call ``OPTEE_MSG_CMD_DO_BOTTOM_HALF``. This +call is done from the thread assisting the interrupt handler. This is a +building block for OP-TEE OS in secure world to implement the top half and +bottom half style of device drivers. + AMD-TEE driver ==============
Adds a section on notifications used by OP-TEE, synchronous and asynchronous. Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> --- Documentation/staging/tee.rst | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)