pmac SMP support broken?

Nathan Sheeley nsheeley at
Wed Jun 16 00:29:00 EST 1999

Has anyone tried to build/run a pmac SMP kernel with a recent (2.2.9)
version of Linux?  

	o I've got a 9500 with 2 604e/200MHz.
	o A UP kernel works fine.  
	o Compliling the same kernel with the SMP support box checked results in
	  a kernel that doesn't boot on UP(a G3) or SMP(the 9500) machines. 
	o I also replaced the dual card with a single 133 MHz CPU, which also fails 
    to boot the SMP kernel.

Can I expect a SMP kernel to boot on a UP?  I thought so, although it might
be slower than a UP kernel on a UP.

The symptoms are that it gets to the point of "opening the display", which
activates the display (all white, I assume painted that way by OF), prints 
"copying OF device tree...done" and stops.  

Also, I was poking around in arch/ppc/kernel/head.S and I noticed this:

  oris  r18,r8,0x20000000 at h
  oris  r21,r11,(KERNELBASE+0x20000000)@h
  mtspr DBAT2L,r18    /* N.B. 6xx (not 601) have valid */
  mtspr DBAT2U,r21    /* bit in upper BAT register */
  mtspr IBAT2L,r28
               ^^^^^^^^^^^^^^^^Wouldn't r18 make more sense here?
  mtspr IBAT2U,r21    

Nathan Sheeley

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