Subject: Re: [PATCH v2] net: filter: BPF 'JIT' compiler for PPC64

From: Benjamin Herrenschmidt <[email-masked]>
Date: Tue, 19 Jul 2011 17:55:35 +1000

On Tue, 2011-07-19 at 08:51 +0200, Eric Dumazet wrote:

> > +		case BPF_S_ANC_CPU:
> > +#ifdef CONFIG_SMP
> > +			/*
> > +			 * PACA ptr is r13:
> > +			 * raw_smp_processor_id() = local_paca->paca_index
> > +			 */
> 
> This could break if one day linux supports more than 65536 cpus :)
> 
> > +			PPC_LHZ_OFFS(r_A, 13,
> > +				     offsetof(struct paca_struct, paca_index));
> > +#else
> > +			PPC_LI(r_A, 0);
> > +#endif
> > +			break;

As would our implementation of raw_smp_processor_id() and our
spinlocks :-) I don't think we need to fix that -now- but you are
welcome to add something like a
BUILD_BUG_ON(sizeof(local_paca->paca_index) != 2); as a reminder :-)

Cheers,
Ben.