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Subject: Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Kumar Gala <galak@kernel.crashing.org>
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Date: Thu, 24 Apr 2008 17:18:57 +1000
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On Thu, 2008-04-24 at 00:37 -0500, Kumar Gala wrote:
> +       /*
> +        * interrupt stacks must be under 256MB, we cannot afford to
> take
> +        * SLB misses on them.
> +        */
> +       for_each_possible_cpu(i) {
> +               softirq_ctx[i] = (struct thread_info *)
> +                       __va(lmb_alloc_base(THREAD_SIZE,
> +                                           THREAD_SIZE, 0x10000000));
> +               hardirq_ctx[i] = (struct thread_info *)
> +                       __va(lmb_alloc_base(THREAD_SIZE,
> +                                           THREAD_SIZE, 0x10000000));
> +       }
> +

The comment is a bit bogus :-) (about SLB misses). lowmem is your limit
I think. Also, why not share the code with ppc64 ?

Ben.