v5 patchset of the AMDKFD driver has just been released for kernel community review [PATCH v5 00/24] AMDKFD Kernel Driver
Next week I expect the HSA RT to be Open Sourced. Together with the Open Source OpenCL compiler, users will now be able to run OpenCL kernels over HSA in Linux! Look at the v5 cover letter for a brief overview
Phoronix article about AMD HSA release: [Phoronix] AMD Is Prepared To Release A Complete User-Space Open-Source Stack For HSA