On Thu, 25 Jun 2020 at 18:22, Maxim Uvarov <maxim.uvarov@xxxxxxxxxx> wrote: > > On Wed, 24 Jun 2020 at 18:44, Jerome Forissier <jerome@xxxxxxxxxxxxx> wrote: > > > > > > > > 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 > > I think your description is correct. But I think this problem would > be solved outside of the current patchset. > All places should use one single format (LE): I guess you missed the point that uuid_t is implemented in BE format in the kernel which is compliant as per RFC 4122. > - internal optee representation; > - device enumeration pta; > - this kernel driver which creates sysfs entry and sets > uid_copy(&optee_device->id.uuid, device_uuid); > - matching function; > - drivers use UUID_INIT(); See carefully the implementation of UUID_INIT() which is in BE format. -Sumit > > In that way everything will be consistent. But it will require > changing other pieces, not just the kernel. While > these patches add functionality to support current device enumeration > in optee os. > So I think this version is ok to be applied. > > Regards, > Maxim.
