From patchwork Fri Jul 17 16:53:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ilya Leoshkevich X-Patchwork-Id: 1331340 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4B7cgy6DfTz9sR4 for ; Sat, 18 Jul 2020 02:55:42 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726530AbgGQQzk (ORCPT ); Fri, 17 Jul 2020 12:55:40 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:63814 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726293AbgGQQzk (ORCPT ); Fri, 17 Jul 2020 12:55:40 -0400 Received: from pps.filterd (m0187473.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06HGZgiJ060100; Fri, 17 Jul 2020 12:55:27 -0400 Received: from ppma03fra.de.ibm.com (6b.4a.5195.ip4.static.sl-reverse.com [149.81.74.107]) by mx0a-001b2d01.pphosted.com with ESMTP id 32792yeph9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 17 Jul 2020 12:55:26 -0400 Received: from pps.filterd (ppma03fra.de.ibm.com [127.0.0.1]) by ppma03fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06HGntZm010477; Fri, 17 Jul 2020 16:55:24 GMT Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by ppma03fra.de.ibm.com with ESMTP id 327527kh09-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 17 Jul 2020 16:55:24 +0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06HGtLG331523320 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 17 Jul 2020 16:55:21 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EF0BDA405B; Fri, 17 Jul 2020 16:55:20 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 68A54A405F; Fri, 17 Jul 2020 16:55:20 +0000 (GMT) Received: from localhost.localdomain (unknown [9.145.6.1]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 17 Jul 2020 16:55:20 +0000 (GMT) From: Ilya Leoshkevich To: Alexei Starovoitov , Daniel Borkmann Cc: bpf@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Ilya Leoshkevich , Seth Forshee Subject: [PATCH 2/5] s390/bpf: fix sign extension in branch_ku Date: Fri, 17 Jul 2020 18:53:23 +0200 Message-Id: <20200717165326.6786-3-iii@linux.ibm.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200717165326.6786-1-iii@linux.ibm.com> References: <20200717165326.6786-1-iii@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-07-17_08:2020-07-17,2020-07-17 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 mlxlogscore=999 priorityscore=1501 lowpriorityscore=0 clxscore=1015 adultscore=0 impostorscore=0 spamscore=0 malwarescore=0 bulkscore=0 mlxscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007170117 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Both signed and unsigned variants of BPF_JMP | BPF_K require sign-extending the immediate. JIT emits cgfi for the signed case, which is correct, and clgfi for the unsigned case, which is not correct: clgfi zero-extends the immediate. s390 does not provide an instruction that does sign-extension and unsigned comparison at the same time. Therefore, fix by first loading the sign-extended immediate into work register REG_1 and proceeding as if it's BPF_X. Fixes: 4e9b4a6883dd ("s390/bpf: Use relative long branches") Reported-by: Seth Forshee Signed-off-by: Ilya Leoshkevich Tested-by: Seth Forshee --- arch/s390/net/bpf_jit_comp.c | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 8fe7bdfc8d15..67608f6092f8 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -1507,21 +1507,10 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, } break; branch_ku: - is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; - /* clfi or clgfi %dst,imm */ - EMIT6_IMM(is_jmp32 ? 0xc20f0000 : 0xc20e0000, - dst_reg, imm); - if (!is_first_pass(jit) && - can_use_rel(jit, addrs[i + off + 1])) { - /* brc mask,off */ - EMIT4_PCREL_RIC(0xa7040000, - mask >> 12, addrs[i + off + 1]); - } else { - /* brcl mask,off */ - EMIT6_PCREL_RILC(0xc0040000, - mask >> 12, addrs[i + off + 1]); - } - break; + /* lgfi %w1,imm (load sign extend imm) */ + src_reg = REG_1; + EMIT6_IMM(0xc0010000, src_reg, imm); + goto branch_xu; branch_xs: is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; if (!is_first_pass(jit) &&