From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kumar Gala Subject: Re: [PATCH v2] net: filter: BPF 'JIT' compiler for PPC64 Date: Tue, 19 Jul 2011 01:59:17 -0500 Message-ID: <51978BAA-10A1-483D-B551-CCC2B69C72EA@kernel.crashing.org> References: <4E23E5C3.1070209@ozlabs.org> <4E24E867.9050909@ozlabs.org> Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Cc: linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org To: Matt Evans Return-path: Received: from gate.crashing.org ([63.228.1.57]:49429 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752089Ab1GSG7Z convert rfc822-to-8bit (ORCPT ); Tue, 19 Jul 2011 02:59:25 -0400 In-Reply-To: <4E24E867.9050909@ozlabs.org> Sender: netdev-owner@vger.kernel.org List-ID: On Jul 18, 2011, at 9:13 PM, Matt Evans wrote: > 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 > --- > > V2: Removed some cut/paste woe in setting SEEN_X even on writes. > Merci for le review, Eric! > > arch/powerpc/Kconfig | 1 + > arch/powerpc/Makefile | 3 +- > arch/powerpc/include/asm/ppc-opcode.h | 40 ++ > arch/powerpc/net/Makefile | 4 + > arch/powerpc/net/bpf_jit.S | 138 +++++++ can we rename to bpf_jit_64.S, since this doesn't work on PPC32. > arch/powerpc/net/bpf_jit.h | 227 +++++++++++ > arch/powerpc/net/bpf_jit_comp.c | 690 +++++++++++++++++++++++++++++++++ same here, or split between bpf_jit_comp.c (shared between ppc32 & ppc64) and bpf_jit_comp_64.c - k