From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2879036-1517590825-2-18421289725314164450 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES unknown, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1517590824; b=fWbGYw1O13cfLUZIwm41FLg8LbDeUpHoyN/3a0Tht9HF/rx Qc+g2zrRCBtTI3jSgMhNzqcmfD6dAq1nVGDXwjhnLAm/7osFkBkh9ylEbEK4104o 9Gk2Z7LA5L9jlgeehN7h1yIbp6uZZk/fK0DSUbzU0fuoC0eFY2Wb4tLmGqAak6lS zHQm+XthcWl/AFBE2VuD5QF/HFr28xwI670Ev30kcqxD2Cz17O09gzuGE7SBZVzQ U17+VRk5AQ6RaGNimYpcf+pAuybKRRBTk1cQWTggf1iTR8ESxMzy3WrE1AxZgP5M zNw7+HQfjqHOWcOnFfjwWHUZjUCIFQmag8Ig5yw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1517590824; bh=jaeK6BraVGvVaVzTOWLz0cQLn4 WXcQ/PydAUZtj0NVg=; b=rO6p6n3XzJxpy6V6tmOWVbfMjgps7WKxmNuy9q2iNC 8X1e8HpRzD4atDF/HHnSIXZ5Ij95wWE+b2XT/2zxcRsHX/oGTcUYhDlMpdtEyq09 FIvFG9+/Vcm528Ey+TWE+k2lwkEKvdNCHYf4cKjxBIzmtbQ07P9WIdRUjDmaliML vjq9GLe8VMdDOO6X8G0+uTrkFtFTA6NQcKgj8PlBO3DbWt2LYTO7N534c0g3E5dl AyIsBU3zfMKkVFXMmloX0O6yhn2Gx2FfXdU09VNhLnE5thF2lNCcrD2/k719hXWO aV/LCESSZRtb+NUVpKRNYS2Oub8SLi+jh/cZbMFlshsQ== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752588AbeBBRAW (ORCPT ); Fri, 2 Feb 2018 12:00:22 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:34722 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752578AbeBBRAU (ORCPT ); Fri, 2 Feb 2018 12:00:20 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Alexei Starovoitov , Daniel Borkmann , "David S. Miller" Subject: [PATCH 4.4 03/67] x86: bpf_jit: small optimization in emit_bpf_tail_call() Date: Fri, 2 Feb 2018 17:57:32 +0100 Message-Id: <20180202140815.552235573@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180202140815.091718203@linuxfoundation.org> References: <20180202140815.091718203@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ upstream commit 84ccac6e7854ebbfb56d2fc6d5bef9be49bb304c ] Saves 4 bytes replacing following instructions : lea rax, [rsi + rdx * 8 + offsetof(...)] mov rax, qword ptr [rax] cmp rax, 0 by : mov rax, [rsi + rdx * 8 + offsetof(...)] test rax, rax Signed-off-by: Eric Dumazet Cc: Alexei Starovoitov Cc: Daniel Borkmann Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- arch/x86/net/bpf_jit_comp.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -269,7 +269,7 @@ static void emit_bpf_tail_call(u8 **ppro EMIT4(0x48, 0x8B, 0x46, /* mov rax, qword ptr [rsi + 16] */ offsetof(struct bpf_array, map.max_entries)); EMIT3(0x48, 0x39, 0xD0); /* cmp rax, rdx */ -#define OFFSET1 47 /* number of bytes to jump */ +#define OFFSET1 43 /* number of bytes to jump */ EMIT2(X86_JBE, OFFSET1); /* jbe out */ label1 = cnt; @@ -278,21 +278,20 @@ static void emit_bpf_tail_call(u8 **ppro */ EMIT2_off32(0x8B, 0x85, -STACKSIZE + 36); /* mov eax, dword ptr [rbp - 516] */ EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */ -#define OFFSET2 36 +#define OFFSET2 32 EMIT2(X86_JA, OFFSET2); /* ja out */ label2 = cnt; EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */ EMIT2_off32(0x89, 0x85, -STACKSIZE + 36); /* mov dword ptr [rbp - 516], eax */ /* prog = array->ptrs[index]; */ - EMIT4_off32(0x48, 0x8D, 0x84, 0xD6, /* lea rax, [rsi + rdx * 8 + offsetof(...)] */ + EMIT4_off32(0x48, 0x8B, 0x84, 0xD6, /* mov rax, [rsi + rdx * 8 + offsetof(...)] */ offsetof(struct bpf_array, ptrs)); - EMIT3(0x48, 0x8B, 0x00); /* mov rax, qword ptr [rax] */ /* if (prog == NULL) * goto out; */ - EMIT4(0x48, 0x83, 0xF8, 0x00); /* cmp rax, 0 */ + EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */ #define OFFSET3 10 EMIT2(X86_JE, OFFSET3); /* je out */ label3 = cnt;