From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1760433AbcIWVkt (ORCPT <rfc822;w@1wt.eu>);
        Fri, 23 Sep 2016 17:40:49 -0400
Received: from www62.your-server.de ([213.133.104.62]:49683 "EHLO
        www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1758358AbcIWVks (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 23 Sep 2016 17:40:48 -0400
Message-ID: <57E5A15A.7090001@iogearbox.net>
Date: Fri, 23 Sep 2016 23:40:42 +0200
From: Daniel Borkmann <daniel@iogearbox.net>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0
MIME-Version: 1.0
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        netdev@vger.kernel.org, Michael Ellerman <mpe@ellerman.id.au>
CC: Alexei Starovoitov <ast@fb.com>,
        "David S. Miller" <davem@davemloft.net>,
        Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Subject: Re: [PATCH 3/3] bpf powerpc: add support for bpf constant blinding
References: <40b65ab2bb3a48837ab047a70887de3ccd70c56b.1474661927.git.naveen.n.rao@linux.vnet.ibm.com> <0ecead168c80b1c3d8a8101595e689ff7c7a735f.1474661927.git.naveen.n.rao@linux.vnet.ibm.com>
In-Reply-To: <0ecead168c80b1c3d8a8101595e689ff7c7a735f.1474661927.git.naveen.n.rao@linux.vnet.ibm.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
X-Authenticated-Sender: daniel@iogearbox.net
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 09/23/2016 10:35 PM, Naveen N. Rao wrote:
> In line with similar support for other architectures by Daniel Borkmann.
>
> 'MOD Default X' from test_bpf without constant blinding:
> 84 bytes emitted from JIT compiler (pass:3, flen:7)
> d0000000058a4688 + <x>:
>     0:	nop
>     4:	nop
>     8:	std     r27,-40(r1)
>     c:	std     r28,-32(r1)
>    10:	xor     r8,r8,r8
>    14:	xor     r28,r28,r28
>    18:	mr      r27,r3
>    1c:	li      r8,66
>    20:	cmpwi   r28,0
>    24:	bne     0x0000000000000030
>    28:	li      r8,0
>    2c:	b       0x0000000000000044
>    30:	divwu   r9,r8,r28
>    34:	mullw   r9,r28,r9
>    38:	subf    r8,r9,r8
>    3c:	rotlwi  r8,r8,0
>    40:	li      r8,66
>    44:	ld      r27,-40(r1)
>    48:	ld      r28,-32(r1)
>    4c:	mr      r3,r8
>    50:	blr
>
> ... and with constant blinding:
> 140 bytes emitted from JIT compiler (pass:3, flen:11)
> d00000000bd6ab24 + <x>:
>     0:	nop
>     4:	nop
>     8:	std     r27,-40(r1)
>     c:	std     r28,-32(r1)
>    10:	xor     r8,r8,r8
>    14:	xor     r28,r28,r28
>    18:	mr      r27,r3
>    1c:	lis     r2,-22834
>    20:	ori     r2,r2,36083
>    24:	rotlwi  r2,r2,0
>    28:	xori    r2,r2,36017
>    2c:	xoris   r2,r2,42702
>    30:	rotlwi  r2,r2,0
>    34:	mr      r8,r2
>    38:	rotlwi  r8,r8,0
>    3c:	cmpwi   r28,0
>    40:	bne     0x000000000000004c
>    44:	li      r8,0
>    48:	b       0x000000000000007c
>    4c:	divwu   r9,r8,r28
>    50:	mullw   r9,r28,r9
>    54:	subf    r8,r9,r8
>    58:	rotlwi  r8,r8,0
>    5c:	lis     r2,-17137
>    60:	ori     r2,r2,39065
>    64:	rotlwi  r2,r2,0
>    68:	xori    r2,r2,39131
>    6c:	xoris   r2,r2,48399
>    70:	rotlwi  r2,r2,0
>    74:	mr      r8,r2
>    78:	rotlwi  r8,r8,0
>    7c:	ld      r27,-40(r1)
>    80:	ld      r28,-32(r1)
>    84:	mr      r3,r8
>    88:	blr
>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>

Acked-by: Daniel Borkmann <daniel@iogearbox.net>