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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	Matt Evans <matt@ozlabs.org>
Subject: Re: [PATCH v2] net: filter: BPF 'JIT' compiler for PPC64
Date: Tue, 19 Jul 2011 17:55:35 +1000	[thread overview]
Message-ID: <1311062135.25044.409.camel@pasglop> (raw)
In-Reply-To: <1311058260.16961.12.camel@edumazet-laptop>

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.

WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Matt Evans <matt@ozlabs.org>,
	netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] net: filter: BPF 'JIT' compiler for PPC64
Date: Tue, 19 Jul 2011 17:55:35 +1000	[thread overview]
Message-ID: <1311062135.25044.409.camel@pasglop> (raw)
In-Reply-To: <1311058260.16961.12.camel@edumazet-laptop>

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.



  reply	other threads:[~2011-07-19  7:55 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-18  7:50 [PATCH] net: filter: BPF 'JIT' compiler for PPC64 Matt Evans
2011-07-18  8:39 ` Eric Dumazet
2011-07-18 19:42   ` David Miller
2011-07-18 19:42     ` David Miller
2011-07-18 20:05     ` Eric Dumazet
2011-07-18 20:05       ` Eric Dumazet
2011-07-19  1:21     ` Matt Evans
2011-07-19  1:21       ` Matt Evans
2011-07-19  2:13 ` [PATCH v2] " Matt Evans
2011-07-19  6:51   ` Eric Dumazet
2011-07-19  6:51     ` Eric Dumazet
2011-07-19  7:55     ` Benjamin Herrenschmidt [this message]
2011-07-19  7:55       ` Benjamin Herrenschmidt
2011-07-19  9:06       ` Eric Dumazet
2011-07-19  9:06         ` Eric Dumazet
2011-07-19  9:22         ` Benjamin Herrenschmidt
2011-07-19  9:22           ` Benjamin Herrenschmidt
2011-07-19  6:59   ` Kumar Gala
2011-07-19  6:59     ` Kumar Gala
2011-07-19  7:06     ` Matt Evans
2011-07-19  7:06       ` Matt Evans
2011-07-19  7:17       ` Kumar Gala
2011-07-19  7:17         ` Kumar Gala
2011-07-19  7:23         ` Matt Evans
2011-07-19  7:23           ` Matt Evans
2011-07-21  1:51   ` [PATCH v3] " Matt Evans
2011-07-21  5:00     ` Eric Dumazet
2011-07-21  5:00       ` Eric Dumazet
2011-07-21 19:47     ` David Miller
2011-07-21 19:47       ` David Miller

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