On 6/24/20 5:21 PM, James Bottomley wrote: > On Wed, 2020-06-24 at 16:17 +0530, Sumit Garg wrote: >> Apologies for delay in my reply as I was busy with some other stuff. >> >> On Fri, 19 Jun 2020 at 20:30, James Bottomley >> <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > [...] >>> it's about consistency with what the kernel types mean. When some >>> checker detects your using little endian operations on a big endian >>> structure (like in the prink for instance) they're going to keep >>> emailing you about it. >> >> As mentioned above, using different terminology is meant to cause >> more confusion than just difference in endianness which is manageable >> inside TEE. >> >> And I think it's safe to say that the kernel implements UUID in big >> endian format and thus uses %pUb whereas OP-TEE implements UUID in >> little endian format and thus uses %pUl. > > So what I think you're saying is that if we still had uuid_be and > uuid_le you'd use uuid_le, because that's exactly the structure > described in the docs. But because we renamed > > uuid_be -> uuid_t > uuid_le -> guid_t > > You can't use guid_t as a kernel type because it has the wrong name? Let me try to clear the confusion that I introduce myself I believe :-/ IMO: - optee_register_device(const uuid_t *device_uuid) *is* the correct prototype. - device_uuid is *guaranteed* to be BE because OP-TEE makes this guarantee (it converts from its internal LE representation to BE when enumerating the devices, but it doesn't matter to the kernel). - Therefore %pUb is the correct format. I'm sorry for doubting the BE order initially. I am so used to OP-TEE using LE internally, that I missed the fact that we have an explicit conversion... Does this sound good? Thanks, -- Jerome
