On Mon, Jan 28, 2019 at 07:20:43PM +0100, Christophe Leroy wrote: > I'm wondering what CONFIG_RTAS is. It makes use of one of the SPRN_SPRG, > ie SPRN_SPRG2. > > What are the CPUs concerned by RTAS ? Is there any of the old CPUs which > have only 4 SPRGs (eg the 601), or could we use one in SPRG4-7 for it > and reuse SPRG2 for something else ?
RTAS (run-time abstraction services) is as old as PowerPC itself. Yes there is RTAS on various 6xx, and those do not have any SPRGs not defined in the architecture. RTAS is a feature of the firmware, or of the platform you could say. Not a feature of CPUs. Segher
