On Tue, 2010-05-11 at 14:59 +1000, Anton Blanchard wrote: > Author: Milton Miller <milt...@bga.com> > > On large machines we are running out of room below 256MB. In some cases we > only need to ensure the allocation is in the first segment, which may be > 256MB or 1TB. > > Add slb0_limit and use it to specify the upper limit for the irqstack and > emergency stacks. > > On a large ppc64 box, this fixes a panic at boot when the crashkernel= > option is specified (previously we would run out of memory below 256MB). > > Signed-off-by: Milton Miller <milt...@bga.com> > Signed-off-by: Anton Blanchard <an...@samba.org> > --- > > Some things we should add: > > - Specify a more intelligent limit for BookE > - The allocation of the PACAs should use this limit too
We access the PACA from real mode?
> Index: linux-2.6/arch/powerpc/kernel/setup_64.c
> ===================================================================
> --- linux-2.6.orig/arch/powerpc/kernel/setup_64.c 2010-04-22
> 17:23:42.000000000 +1000
> +++ linux-2.6/arch/powerpc/kernel/setup_64.c 2010-04-30 09:46:15.000000000
> +1000
> @@ -424,9 +424,18 @@ void __init setup_system(void)
> DBG(" <- setup_system()\n");
> }
>
> +static u64 slb0_limit(void)
> +{
> + if (cpu_has_feature(CPU_FTR_1T_SEGMENT)) {
> + return 1UL << SID_SHIFT_1T;
> + }
> + return 1UL << SID_SHIFT;
> +}
I take it there's no chance the CPU feature is there but we're using 256
for whatever reason?
cheers
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