Jorge,
On 03.10.18 16:56, Jorge Ramirez-Ortiz wrote:
On 10/03/2018 03:48 PM, Volodymyr Babchuk wrote:
Hi Jorge,
On 03.10.18 16:31, Jorge Ramirez-Ortiz wrote:
On 10/03/2018 03:17 PM, Jens Wiklander wrote:
On Wed, Oct 3, 2018 at 2:27 PM, Jorge Ramirez-Ortiz jramirez@baylibre.com wrote:
I am upstreaming TF-A support for the Renesas R-car gen3 platforms [1].
In order to prevent the boot cpu from being switched off (hotpluged) I am having to work around the fact that OPTEE_OS does not support MIGRATE_INFO_TYPE or MIGRATE_INFO_UP_CPU.
Why should OP-TEE care about that?
the boot cpu boots OP-TEE; when OP-TEE has migration requirements the boot cpu must not be hot-plugged. So OP-TEE in away should care about implementing those interfaces (unless every OP-TEE ever created is guaranteed to have no migration restrictions).
Aren't you confusing OP-TEE with TEE?
I dont claim to know a lot about this but I dont think so, isnt OP-TEE the one implementing to the PSCI API? https://github.com/OP-TEE/optee_os/blob/master/core/arch/arm/sm/psci.c#L70
That piece of code is a secure monitor for ARMv7 systems, where ARM TF is absent. OP-TEE implements very simple secure monitor with PSCI support for such systems. But it is preferred to have full-scale Secure Monitor like ARM-TF. In the latter case, OP-TEE does not bothers about PSCI at all.
On ARMv7, where firmware is absent, it is possible to built OP-TEE with embedded Secure Monitor and in this case OP-TEE will act both as Trusted Execution Environment (TEE) and as firmware (for example, by providing PSCI services). If I remember right, this is due to ARMv7 limitation: Secure Monitor mode has no separate MMU context and it shares MMU state with Secure SVC mode. Thus, it is quite hard to create separate firmware (like ARM TF).
Luckily, this was fixed on ARMv8 and we now have separate firmware (ARM-TF on most systems) and SecureOS/TEE (like OP-TEE).
I'd assume that the TrustedOS should just query the TEE?
ARM TF have SPD module written specially for OP-TEE, so ARM-TF already knows a lot about how OP-TEE works. So, I see no sense, why ARM-TF should query OP-TEE about things that are not subjected to change.