On Fri, Feb 07, 2003 at 02:56:30PM -0700, Kerl, John wrote: > > Hello all, > > There have been some recent posts about Linux & Virtex-II Pro > (FPGA with PPC405 hard core). & apparently people have it working. > > One question before I start, though: > > Of course the kernel starts at *virtual* address 0xc0000000, regardless > of the processor. But my understanding is that certain processors have > zero-based *physical* addresses for RAM, and some don't -- x86 of course > being an example of the former, and ARM being an example of the latter. > I believe that PPC is an example of the former. Certainly our MPC857T > board, and all the other boards of which I'm aware, have RAM starting at > physical address 0x00000000. >
The 405 has an exception vector pointer register, which is initialized by linux (linuxppc_2_4_devel cvs tree) with the kernel base. So in principle it should be possible to have linux run on a system without memory at address 0. I have never tried this however. Cheers, Peter. ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
