From patchwork Fri May 1 02:02:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luke Nelson X-Patchwork-Id: 1281049 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@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=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=cs.washington.edu Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=cs.washington.edu header.i=@cs.washington.edu header.a=rsa-sha256 header.s=goo201206 header.b=Lbm9BFkD; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49CwVr0Wzrz9sRY for ; Fri, 1 May 2020 12:02:28 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728115AbgEACCX (ORCPT ); Thu, 30 Apr 2020 22:02:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1727889AbgEACCV (ORCPT ); Thu, 30 Apr 2020 22:02:21 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D62AC035495 for ; Thu, 30 Apr 2020 19:02:21 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id y25so962277pfn.5 for ; Thu, 30 Apr 2020 19:02:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cs.washington.edu; s=goo201206; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=tvELNqxAjbVBxzf7Gp8Es5Dk4+hyrWQ5hnmsAjacAVU=; b=Lbm9BFkDtR3zwyIVc/ySdZUYZHeNhbKhjemSORm2CSkVwtDvAaLi2nmQLu4HdG8HAP xyTzFSKkUYaWO+GOCMXPAaw/qbYZ5JpiK306mVqmmsll4hg+J+DUUV0v5f7cOdinzuNj 0HERqZdp+4w/0uX8Fl/ETX9miRiHoTqHVJeZE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=tvELNqxAjbVBxzf7Gp8Es5Dk4+hyrWQ5hnmsAjacAVU=; b=dgA0PskH9qJXp+Rf240Ps/iNReJgparU53AJ6D7wPvCmAtdjXDITUdDvmVcrjnRfr+ y+6DAqzLM9GT1wyJbN4RpN/4Dx+tfOPs79Nq1qP/5nHpMo8Uc7YOzsX6rC1XNdMhe7wP rd9ZgFYTyahKsSgKkgCiSjHOYo8CfjkHgzLfk6uJ9Cdqhuv8hepCVD86asyWTufllSNn s//yR93/RcTGeu2Hg3a7jGvuSO9wemDBzME68SU6vsJMRoU2mp3z+SVyYyeGLzVQ3clR 3Qal2Gsxypco8brHeqs9KtnN626dHqu7/ODbtbXzGkzylfnnhU+rrqmembmWC+4IqplD dbiw== X-Gm-Message-State: AGi0PuZXbVtJNuN4+VWgpcMuYIFFMEFnGCOXD7k1gm7XgQA6TAs9D8JK J7H4B/VyJu8YjQMjimq+DM+u8g== X-Google-Smtp-Source: APiQypJQTsqMdFZLcemxJPj2JqzPwYcmFse4CYahCcdsJKdasZVpwItAmZsTocEKxZjdGIBnXdUizg== X-Received: by 2002:a63:6d83:: with SMTP id i125mr1999548pgc.365.1588298540989; Thu, 30 Apr 2020 19:02:20 -0700 (PDT) Received: from localhost.localdomain (c-73-53-94-119.hsd1.wa.comcast.net. [73.53.94.119]) by smtp.gmail.com with ESMTPSA id fy21sm802915pjb.25.2020.04.30.19.02.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Apr 2020 19:02:20 -0700 (PDT) From: Luke Nelson X-Google-Original-From: Luke Nelson To: bpf@vger.kernel.org Cc: Luke Nelson , Xi Wang , Shubham Bansal , Russell King , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , John Fastabend , KP Singh , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next 1/2] bpf, arm: Optimize ALU64 ARSH X using orrpl conditional instruction Date: Thu, 30 Apr 2020 19:02:09 -0700 Message-Id: <20200501020210.32294-2-luke.r.nels@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200501020210.32294-1-luke.r.nels@gmail.com> References: <20200501020210.32294-1-luke.r.nels@gmail.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch optimizes the code generated by emit_a32_arsh_r64, which handles the BPF_ALU64 BPF_ARSH BPF_X instruction. The original code uses a conditional B followed by an unconditional ORR. The optimization saves one instruction by removing the B instruction and using a conditional ORR (with an inverted condition). Example of the code generated for BPF_ALU64_REG(BPF_ARSH, BPF_REG_0, BPF_REG_1), before optimization: 34: rsb ip, r2, #32 38: subs r9, r2, #32 3c: lsr lr, r0, r2 40: orr lr, lr, r1, lsl ip 44: bmi 0x4c 48: orr lr, lr, r1, asr r9 4c: asr ip, r1, r2 50: mov r0, lr 54: mov r1, ip and after optimization: 34: rsb ip, r2, #32 38: subs r9, r2, #32 3c: lsr lr, r0, r2 40: orr lr, lr, r1, lsl ip 44: orrpl lr, lr, r1, asr r9 48: asr ip, r1, r2 4c: mov r0, lr 50: mov r1, ip Tested on QEMU using lib/test_bpf and test_verifier. Co-developed-by: Xi Wang Signed-off-by: Xi Wang Signed-off-by: Luke Nelson --- arch/arm/net/bpf_jit_32.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index bf85d6db4931..48b89211ee5c 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -860,8 +860,8 @@ static inline void emit_a32_arsh_r64(const s8 dst[], const s8 src[], emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx); emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx); emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx); - _emit(ARM_COND_MI, ARM_B(0), ctx); - emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASR, tmp2[0]), ctx); + _emit(ARM_COND_PL, + ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASR, tmp2[0]), ctx); emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_ASR, rt), ctx); arm_bpf_put_reg32(dst_lo, ARM_LR, ctx);