From patchwork Thu May 12 07:45:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hari Bathini X-Patchwork-Id: 12847272 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33DC4C433F5 for ; Thu, 12 May 2022 07:47:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351168AbiELHra (ORCPT ); Thu, 12 May 2022 03:47:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351181AbiELHrX (ORCPT ); Thu, 12 May 2022 03:47:23 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E37C91B57A0; Thu, 12 May 2022 00:47:18 -0700 (PDT) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 24C4tf1p011245; Thu, 12 May 2022 07:46:49 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=sJNqtW7ebykqIJ6MGEZr6hWe/bMGGF1zGAs008xihKQ=; b=U7qpwa6FFc9DwyTK5ybiNdjGISAEZUA9ayUluK9WVY6jih3efRrAToAKpI24Hf2wE4De 2zSdIjIaHa2uRa/vFwsv120UOekDU8AtOUZ+nceOQxPwvJBUqL+ku7Affz4cdoDMjHn5 +eTOS68WeLAGKR6Kup5yzbsRTTPTeuLCj+dIiy8x88/29QY9bLYgZHakITdVSuNbeJF4 UKd2KSGGrbu3L2MSp0orpG5VL+uWDw0+a6SfDkEfyH1cVc5Vys/E/a/d4xbHOK10rQUy UyipFFpkbq7RpjZp9fxLpRWPSZEJy92wiNDSsOfWA4Z2NE9OuCOHMWNCdgHKwyxi/dEO zA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3g0un2jxek-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 12 May 2022 07:46:48 +0000 Received: from m0098404.ppops.net (m0098404.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 24C7Ia6b022328; Thu, 12 May 2022 07:46:48 GMT Received: from ppma01fra.de.ibm.com (46.49.7a9f.ip4.static.sl-reverse.com [159.122.73.70]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3g0un2jxd8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 12 May 2022 07:46:47 +0000 Received: from pps.filterd (ppma01fra.de.ibm.com [127.0.0.1]) by ppma01fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 24C7bckD028290; Thu, 12 May 2022 07:46:44 GMT Received: from b06avi18878370.portsmouth.uk.ibm.com (b06avi18878370.portsmouth.uk.ibm.com [9.149.26.194]) by ppma01fra.de.ibm.com with ESMTP id 3fwgd8n500-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 12 May 2022 07:46:44 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 24C7kKCb29360470 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 May 2022 07:46:20 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9DAC7A4051; Thu, 12 May 2022 07:46:41 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6BC89A4040; Thu, 12 May 2022 07:46:33 +0000 (GMT) Received: from hbathini-workstation.ibm.com.com (unknown [9.211.109.30]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 12 May 2022 07:46:33 +0000 (GMT) From: Hari Bathini To: bpf@vger.kernel.org, linuxppc-dev Cc: Michael Ellerman , "Naveen N. Rao" , Christophe Leroy , netdev@vger.kernel.org, Benjamin Herrenschmidt , Paul Mackerras , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Jordan Niethe Subject: [PATCH 5/5] bpf ppc32: Add instructions for atomic_[cmp]xchg Date: Thu, 12 May 2022 13:15:46 +0530 Message-Id: <20220512074546.231616-6-hbathini@linux.ibm.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220512074546.231616-1-hbathini@linux.ibm.com> References: <20220512074546.231616-1-hbathini@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: r8QtyRJIHN0NPICWmDmD1c4VvQ9qLDwN X-Proofpoint-ORIG-GUID: DS3bfz7Bz7Ook08vLsStW7dHE20VY3uT X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-11_07,2022-05-12_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 adultscore=0 impostorscore=0 mlxscore=0 suspectscore=0 priorityscore=1501 clxscore=1015 lowpriorityscore=0 bulkscore=0 malwarescore=0 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205120034 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This adds two atomic opcodes BPF_XCHG and BPF_CMPXCHG on ppc32, both of which include the BPF_FETCH flag. The kernel's atomic_cmpxchg operation fundamentally has 3 operands, but we only have two register fields. Therefore the operand we compare against (the kernel's API calls it 'old') is hard-coded to be BPF_REG_R0. Also, kernel's atomic_cmpxchg returns the previous value at dst_reg + off. JIT the same for BPF too with return value put in BPF_REG_0. BPF_REG_R0 = atomic_cmpxchg(dst_reg + off, BPF_REG_R0, src_reg); Signed-off-by: Hari Bathini --- arch/powerpc/net/bpf_jit_comp32.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c index 5604ae1b60ab..4690fd6e9e52 100644 --- a/arch/powerpc/net/bpf_jit_comp32.c +++ b/arch/powerpc/net/bpf_jit_comp32.c @@ -829,6 +829,23 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * /* we're done if this succeeded */ PPC_BCC_SHORT(COND_NE, tmp_idx); break; + case BPF_CMPXCHG: + /* Compare with old value in BPF_REG_0 */ + EMIT(PPC_RAW_CMPW(bpf_to_ppc(BPF_REG_0), _R0)); + /* Don't set if different from old value */ + PPC_BCC_SHORT(COND_NE, (ctx->idx + 3) * 4); + fallthrough; + case BPF_XCHG: + /* store new value */ + EMIT(PPC_RAW_STWCX(src_reg, tmp_reg, dst_reg)); + PPC_BCC_SHORT(COND_NE, tmp_idx); + /* + * Return old value in src_reg for BPF_XCHG & + * BPF_REG_0 for BPF_CMPXCHG. + */ + EMIT(PPC_RAW_MR(imm == BPF_XCHG ? src_reg : bpf_to_ppc(BPF_REG_0), + _R0)); + break; default: pr_err_ratelimited("eBPF filter atomic op code %02x (@%d) unsupported\n", code, i);