From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v3] net: filter: BPF 'JIT' compiler for PPC64 Date: Thu, 21 Jul 2011 12:47:57 -0700 (PDT) Message-ID: <20110721.124757.1998243180954846915.davem@davemloft.net> References: <4E23E5C3.1070209@ozlabs.org> <4E24E867.9050909@ozlabs.org> <4E278604.5080605@ozlabs.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org To: matt@ozlabs.org Return-path: Received: from shards.monkeyblade.net ([198.137.202.13]:35874 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752313Ab1GUTuF (ORCPT ); Thu, 21 Jul 2011 15:50:05 -0400 In-Reply-To: <4E278604.5080605@ozlabs.org> Sender: netdev-owner@vger.kernel.org List-ID: From: Matt Evans Date: Thu, 21 Jul 2011 11:51:00 +1000 > An implementation of a code generator for BPF programs to speed up packet > filtering on PPC64, inspired by Eric Dumazet's x86-64 version. > > Filter code is generated as an ABI-compliant function in module_alloc()'d mem > with stackframe & prologue/epilogue generated if required (simple filters don't > need anything more than an li/blr). The filter's local variables, M[], live in > registers. Supports all BPF opcodes, although "complicated" loads from negative > packet offsets (e.g. SKF_LL_OFF) are not yet supported. > > There are a couple of further optimisations left for future work; many-pass > assembly with branch-reach reduction and a register allocator to push M[] > variables into volatile registers would improve the code quality further. > > This currently supports big-endian 64-bit PowerPC only (but is fairly simple > to port to PPC32 or LE!). > > Enabled in the same way as x86-64: > > echo 1 > /proc/sys/net/core/bpf_jit_enable > > Or, enabled with extra debug output: > > echo 2 > /proc/sys/net/core/bpf_jit_enable > > Signed-off-by: Matt Evans Applied.