On Thu, 17 Jun 2021 at 11:40, Jens Wiklander jens.wiklander@linaro.org wrote:
Hi Sumit,
On Thu, Jun 17, 2021 at 6:33 AM Sumit Garg sumit.garg@linaro.org wrote:
Hi Jens,
On Wed, 16 Jun 2021 at 16:07, Jens Wiklander jens.wiklander@linaro.org wrote:
Hi all,
This adds support for asynchronous notifications from OP-TEE in secure world to the OP-TEE driver. This allows a design with a top half and bottom half type of driver where the top half runs in secure interrupt context and a notifications tells normal world to schedule a yielding call to do the bottom half processing.
An interrupt is used to notify the driver that there are asynchronous notifications pending.
It looks like a nice feature. I would like to get hands on with this. Can I test this feature on Qemu?
Absolutely, you can get this into the normal OP-TEE development repo setup with: repo init -u https://github.com/OP-TEE/manifest.git -m default.xml repo sync Update optee_os with https://github.com/jenswi-linaro/optee_os/tree/async_notif_v2 Update linux with https://github.com/jenswi-linaro/linux-1/tree/async_notif_v2 cd build make all -j... make run-only
If you type anything at the secure console you'll notice how it changes behaviour once the Linux kernel has booted.
Thanks for sharing instructions as I now got some time to test and deep dive into this feature. It looks like a pretty useful feature to realize interrupt support in the secure world in its true sense. This feature works for me as per your instructions.
I could recognise it's requirement from the time while I was playing with secure timer interrupt support for OP-TEE RNG driver on Developerbox. In that case I had to strip down the secure interrupt handler to a minimum that would just collect entropy and dump into the secure buffer. But with asynchronous notifications support, I could add more functionality like entropy health tests in the bottom half instead of doing those health tests while retrieving entropy from the secure world.
Given that, have you explored the possibility to leverage SGI rather than a platform specific SPI for notifying the normal world? If it's possible to leverage Architecture specific SGI for this purpose then I think this feature will come automatically enabled for every platform without the need to reserve a platform specific SPI.
-Sumit
Cheers, Jens
-Sumit
v2:
- Added documentation
- Converted optee bindings to json-schema and added interrupt property
- Configure notification interrupt from DT instead of getting it from secure world, suggested by Ard Biesheuvel ardb@kernel.org.
Thanks, Jens
Jens Wiklander (7): docs: staging/tee.rst: add a section on OP-TEE notifications dt-bindings: arm: Convert optee binding to json-schema dt-bindings: arm: optee: add interrupt property tee: fix put order in teedev_close_context() tee: add tee_dev_open_helper() primitive optee: separate notification functions optee: add asynchronous notifications
.../bindings/arm/firmware/linaro,optee-tz.txt | 31 --- .../arm/firmware/linaro,optee-tz.yaml | 57 +++++ Documentation/staging/tee.rst | 27 +++ drivers/tee/optee/Makefile | 1 + drivers/tee/optee/call.c | 27 +++ drivers/tee/optee/core.c | 87 +++++-- drivers/tee/optee/notif.c | 226 ++++++++++++++++++ drivers/tee/optee/optee_msg.h | 9 + drivers/tee/optee/optee_private.h | 23 +- drivers/tee/optee/optee_rpc_cmd.h | 31 +-- drivers/tee/optee/optee_smc.h | 75 +++++- drivers/tee/optee/rpc.c | 73 +----- drivers/tee/tee_core.c | 37 ++- include/linux/tee_drv.h | 27 +++ 14 files changed, 576 insertions(+), 155 deletions(-) delete mode 100644 Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.txt create mode 100644 Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml create mode 100644 drivers/tee/optee/notif.c
-- 2.31.1