netdev - Re: [PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF

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Date:	Tue, 7 Jun 2016 15:56:11 -0700
From:	Alexei Starovoitov <alexei.starovoitov@...il.com>
To:	"Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>
Cc:	linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	netdev@...r.kernel.org, mpe@...erman.id.au,
	Matt Evans <matt@...abs.org>,
	Denis Kirjanov <kda@...ux-powerpc.org>,
	Paul Mackerras <paulus@...ba.org>,
	Alexei Starovoitov <ast@...com>,
	Daniel Borkmann <daniel@...earbox.net>,
	"David S. Miller" <davem@...emloft.net>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>
Subject: Re: [PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for extended
 BPF

On Tue, Jun 07, 2016 at 07:02:23PM +0530, Naveen N. Rao wrote:
> PPC64 eBPF JIT compiler.
> 
> Enable with:
> echo 1 > /proc/sys/net/core/bpf_jit_enable
> or
> echo 2 > /proc/sys/net/core/bpf_jit_enable
> 
> ... to see the generated JIT code. This can further be processed with
> tools/net/bpf_jit_disasm.
> 
> With CONFIG_TEST_BPF=m and 'modprobe test_bpf':
> test_bpf: Summary: 305 PASSED, 0 FAILED, [297/297 JIT'ed]
> 
> ... on both ppc64 BE and LE.

Nice. That's even better than on x64 which cannot jit one test:
test_bpf: #262 BPF_MAXINSNS: Jump, gap, jump, ... jited:0 168 PASS
which was designed specifically to hit x64 jit pass limit.
ppc jit has predicatble number of passes and doesn't have this problem
as expected. Great.

> The details of the approach are documented through various comments in
> the code.
> 
> Cc: Matt Evans <matt@...abs.org>
> Cc: Denis Kirjanov <kda@...ux-powerpc.org>
> Cc: Michael Ellerman <mpe@...erman.id.au>
> Cc: Paul Mackerras <paulus@...ba.org>
> Cc: Alexei Starovoitov <ast@...com>
> Cc: Daniel Borkmann <daniel@...earbox.net>
> Cc: "David S. Miller" <davem@...emloft.net>
> Cc: Ananth N Mavinakayanahalli <ananth@...ibm.com>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@...ux.vnet.ibm.com>
> ---
>  arch/powerpc/Kconfig                  |   3 +-
>  arch/powerpc/include/asm/asm-compat.h |   2 +
>  arch/powerpc/include/asm/ppc-opcode.h |  20 +-
>  arch/powerpc/net/Makefile             |   4 +
>  arch/powerpc/net/bpf_jit.h            |  53 +-
>  arch/powerpc/net/bpf_jit64.h          | 102 ++++
>  arch/powerpc/net/bpf_jit_asm64.S      | 180 +++++++
>  arch/powerpc/net/bpf_jit_comp64.c     | 956 ++++++++++++++++++++++++++++++++++
>  8 files changed, 1317 insertions(+), 3 deletions(-)
>  create mode 100644 arch/powerpc/net/bpf_jit64.h
>  create mode 100644 arch/powerpc/net/bpf_jit_asm64.S
>  create mode 100644 arch/powerpc/net/bpf_jit_comp64.c

don't see any issues with the code.
Thank you for working on this.

Acked-by: Alexei Starovoitov <ast@...nel.org>