On Tue, May 13, 2003 at 10:51:45AM +0100, Ladislav Michl wrote: > On Mon, May 12, 2003 at 10:44:08AM -0700, Jun Sun wrote: > > On Mon, May 12, 2003 at 11:56:41AM +0100, Ladislav Michl wrote: > > > Could anyone tell me where is space for exception vectors reserved? Many boards > > > (for example Alchemy Pb1000, Galileo EV96100 or Galileo EV64120A) simply > > > registers all available RAM with add_memory_region call, but I didn't find code > > > which reserves first 0x200 (on most CPUs) for exceptions vectors anywhere. I'd > > > guess there is something obvious what I'm missing. Can you help me to see it? > > > > Kernel only uses memory after the end of kernel image. In that sense, all > > memory before LOADADDR (see arch/mips/Makefile) is reserved. > > I'm afraid, I didn't find any code which does what you're describing here. > But in arch/mips/mm/init.c is function setup_zero_pages which allocates > first (or first eight if CPU has VCE) page(s). Does it do the trick? > Now you are really pushing me. :) I figured that out a while back. I think you can find answers in arch/mips/kernel/setup.c, start_pfn = PFN_UP(__pa(&_end)); I think zero pages are allocated so that all future read-only zero-filled pages can be mapped to them. They are allocated at the beginning of start_pfn, which is also after kernel image. Jun
