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Date: Thu, 13 Feb 2014 23:44:16 +0100
From: Daniel Borkmann <dborkman@redhat.com>
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To: "H. Peter Anvin" <hpa@zytor.com>
CC: Alexei Starovoitov <ast@plumgrid.com>, Ingo Molnar <mingo@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Steven Rostedt <rostedt@goodmis.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Thomas Gleixner <tglx@linutronix.de>,
        Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
        Tom Zanussi <tom.zanussi@linux.intel.com>,
        Jovi Zhangwei <jovi.zhangwei@gmail.com>,
        Eric Dumazet <edumazet@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Arnaldo Carvalho de Melo <acme@infradead.org>,
        Pekka Enberg <penberg@iki.fi>, Arjan van de Ven <arjan@infradead.org>,
        Christoph Hellwig <hch@infradead.org>, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org
Subject: Re: [RFC PATCH v2 tip 0/7] 64-bit BPF insn set and tracing filters
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On 02/13/2014 11:32 PM, H. Peter Anvin wrote:
> On 02/06/2014 05:20 PM, Alexei Starovoitov wrote:
>>
>> I believe that old BPF outlived itself and BPF64 should
>> replace it in all current use cases plus a lot more.
>> It just cannot happen at once.
>> BPF64 can come in. bpf32->bpf64 converter functioning.
>> JIT from bpf64->aarch64 and may be sparc64 needs to be in place.
>> Then old bpf can fade away.
>
> I don't think that is doable any time soon.  Right now pretty much all
> mobile devices, for example, are 32 bits and they really want to use
> syscall filtering for security.  Performance matters greatly there.

Well, if that would be the case, then seccomp would have had JIT support
long ago. ;-) Right now BPF filters with seccomp are not JIT compiled
for _any_ architecture.

> As such, 32-bit JIT support is going to be very important for a long
> time to come.

True, I think that pretty much depends if we can manage to find a way
to cleanly integrate it into net/core/filter.c while still supporting
the old instructions as I've mentioned earlier.

> 	-hpa
>
>