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* [MPC8xx] Initial MMU too low
@ 2010-10-30 11:52 LEROY christophe
  2010-10-30 20:47 ` Benjamin Herrenschmidt
  2010-11-01 17:58 ` Scott Wood
  0 siblings, 2 replies; 3+ messages in thread
From: LEROY christophe @ 2010-10-30 11:52 UTC (permalink / raw)
  To: linuxppc-dev

Hello,

When I build a kernel with DEBUG_LOCK_ALLOC set, I get a kernel which 
has __bss_stop above the C0800000 limit, and then I get a bad page 
exception during the zeroize of the __bss at startup, because the 
initial MMU only maps the first 8Mbytes.

What can I do to fix that ?

Regards
C. Leroy

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [MPC8xx] Initial MMU too low
  2010-10-30 11:52 [MPC8xx] Initial MMU too low LEROY christophe
@ 2010-10-30 20:47 ` Benjamin Herrenschmidt
  2010-11-01 17:58 ` Scott Wood
  1 sibling, 0 replies; 3+ messages in thread
From: Benjamin Herrenschmidt @ 2010-10-30 20:47 UTC (permalink / raw)
  To: LEROY christophe; +Cc: linuxppc-dev

On Sat, 2010-10-30 at 13:52 +0200, LEROY christophe wrote:
> Hello,
> 
> When I build a kernel with DEBUG_LOCK_ALLOC set, I get a kernel which 
> has __bss_stop above the C0800000 limit, and then I get a bad page 
> exception during the zeroize of the __bss at startup, because the 
> initial MMU only maps the first 8Mbytes.
> 
> What can I do to fix that ?

Not much... maybe pin more initial TLBs ?

Ben.

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [MPC8xx] Initial MMU too low
  2010-10-30 11:52 [MPC8xx] Initial MMU too low LEROY christophe
  2010-10-30 20:47 ` Benjamin Herrenschmidt
@ 2010-11-01 17:58 ` Scott Wood
  1 sibling, 0 replies; 3+ messages in thread
From: Scott Wood @ 2010-11-01 17:58 UTC (permalink / raw)
  To: LEROY christophe; +Cc: linuxppc-dev

On Sat, 30 Oct 2010 13:52:24 +0200
LEROY christophe <christophe.leroy@c-s.fr> wrote:

> Hello,
> 
> When I build a kernel with DEBUG_LOCK_ALLOC set, I get a kernel which 
> has __bss_stop above the C0800000 limit, and then I get a bad page 
> exception during the zeroize of the __bss at startup, because the 
> initial MMU only maps the first 8Mbytes.
> 
> What can I do to fix that ?

Under "Advanced setup", select "Pinned Kernel TLBs".  Ignore the "860
ONLY", it applies to all 8xx.

-Scott

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2010-11-01 17:58 UTC | newest]

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2010-10-30 11:52 [MPC8xx] Initial MMU too low LEROY christophe
2010-10-30 20:47 ` Benjamin Herrenschmidt
2010-11-01 17:58 ` Scott Wood

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