On Thu, 26 Jul 2018 at 13:20, Daniel Thompson <daniel.thomp...@linaro.org> wrote: > > On Thu, Jul 26, 2018 at 09:39:37AM +0200, Ard Biesheuvel wrote: > > On 26 July 2018 at 09:36, Daniel Thompson <daniel.thomp...@linaro.org> > > wrote: > > > On Wed, Jul 25, 2018 at 12:04:58PM +0200, Ard Biesheuvel wrote: > > >> On 23 July 2018 at 15:19, Sumit Garg <sumit.g...@linaro.org> wrote: > > >> > OP-TEE is optional on Developerbox controlled via SCP firmware. To > > >> > check > > >> > if we need to delete OP-TEE DT node, we use DRAM1 region info as SCP > > >> > firmware conditionally carves out Secure memory from DRAM1 region. > > >> > > > >> > Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> > > >> > Cc: Leif Lindholm <leif.lindh...@linaro.org> > > >> > Contributed-under: TianoCore Contribution Agreement 1.1 > > >> > Signed-off-by: Sumit Garg <sumit.g...@linaro.org> > > >> > --- > > >> > > > >> > > >> As discussed on IRC, i am not a fan of inferring the presence of > > >> OP-TEE from the base/size values of the first DRAM region. > > >> > > >> Please refer to the existing PCIe code how to read a GPIO in PEI and > > >> set a dynamic PCD accordingly, so you can use its value in > > >> PlatformDxe. > > > > > > For Trusted Firmware I asked Sumit to look for the OP-TEE memory carve > > > out rather than looking at the switches. This was based on concerns > > > about version skew (new C-A53 firmware, old SCP firmware[1]), in > > > particular > > > if TF-A jumps to an OP-TEE that isn't actually loaded the system will > > > fail in a not very transparent way (especially if the user hasn't found > > > the debug UART behind the back panel yet). > > > > > > What is the consequence of passing a DT with OP-TEE present if one is > > > not actually present? Do we at least get as far as bringing up the > > > framebuffer before things explode? > > >
If we pass a DT with OP-TEE and OP-TEE not present, Linux TEE generic driver exits gracefully giving following message: [ 1.976021] optee: probing for conduit method from DT. [ 1.976033] optee: api uid mismatch > > > > Is there any way we can let OP-TEE supply a DT overlay? > > I guess it could implement a secure monitor call to provide it. In > fact I find it a rather pleasing approach. However I think it still loops > us round to pretty much the same question as before. Does TF-A "protec > " a normal world that makes an SMC to an OP-TEE that isn't there by > failing the call in a nice way? > TF-A returns SMC call for OP-TEE as unknown (error code: -1 in "x0" register) if OP-TEE is not present. -Sumit > > Daniel. _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
