From patchwork Thu Dec 3 16:02:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brendan Jackman X-Patchwork-Id: 11949053 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 X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B973AC0018C for ; Thu, 3 Dec 2020 16:04:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 80358207AD for ; Thu, 3 Dec 2020 16:04:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728857AbgLCQD7 (ORCPT ); Thu, 3 Dec 2020 11:03:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726267AbgLCQD7 (ORCPT ); Thu, 3 Dec 2020 11:03:59 -0500 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5824C061A53 for ; Thu, 3 Dec 2020 08:03:12 -0800 (PST) Received: by mail-ej1-x649.google.com with SMTP id k15so955642ejg.8 for ; Thu, 03 Dec 2020 08:03:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=Avg0eeJcHmqqPj9kVJA02JQI6kCCnbENGcaSwjHPh3w=; b=IFtG6Xqy/HIL7S+ghxb9zqtTZkaezrwpXDJBy+3NhXnBPgctfC1hoVNdopgr4BhGoC xzpDUUuz3fCW9BvtFLchGmQKgpZGjmllAl8u+px+FtAFfEWrGXhD7SbeMntG8H11hI+K jS1TWr+CpOYtIJV/yDofrOQfh3QTk3hYvF13V6xqAem/6EJpHqxHDK55/+b0qAf6J95Z 9P5q8If3f/sXCZjtoF7mC8NFePzRNhxQvixpoBePhvGHz5p3cELZMOdIkSM+Wt+BSfbU L+ZmfXazlhg+aVDILuLWuaD6Jt6sKMAilPhhAxLk6vVNFfS/E8CFlpeUeqmohyWGkYch l6SQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Avg0eeJcHmqqPj9kVJA02JQI6kCCnbENGcaSwjHPh3w=; b=XPn0QnPBWE5DWaVcS5IJKby5XK7ttX73jNLjHkFSaJNLSN8kzE1PbEjmtm/KjT6OW0 YSythjDZnMJEpM7sBvrRDJX4AXFh/jQWoqDtKtEVL8JyGzF5cE7BH2CFwzF88sasQt3w Bp0A1Zk7nrnWFoKKG70q4vqxVOffKy4mrO2EEuPR1ki+SIZchw0wJbFp8N0nWxPKuAD+ o7I7g2LWuCDpWYPmF76ckBK309f4WARBnjZ4bvc0brzFQ4PN54AyS5agE7nDHtx4Wkun YHmk/h8TdKQstonAAkPD2IDqWjuzihZNY3qeYAF4XslIblaqFcsJnnZHV0BB07CFtUr3 otNA== X-Gm-Message-State: AOAM530nlmvMgg1+e2u8sp5yNC7qIO/PV3JPeGUijo6N6CDExTzpGV1P qcyxMw2s19JuMlu5YZmlVbibfv75lQTFNJN+yDCcWeXDUOkVOrZvZv9AqXB960Jo0oHZAsF9g/w rvFM7xk434WUoW6bFanWkglL7ALXaraHKdzobHs22yBL9x9D9Ply/f8+BV2nmQ6U= X-Google-Smtp-Source: ABdhPJzuT8NP2QZqSfs5VGNZ/PtzZs7jUmyA8fllEw8LdS22rMv2aLa+JH08iaFSAytfjR0iwSBz1ys9ErjX3w== Sender: "jackmanb via sendgmr" X-Received: from beeg.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:11db]) (user=jackmanb job=sendgmr) by 2002:a17:906:f894:: with SMTP id lg20mr3079697ejb.348.1607011391181; Thu, 03 Dec 2020 08:03:11 -0800 (PST) Date: Thu, 3 Dec 2020 16:02:32 +0000 In-Reply-To: <20201203160245.1014867-1-jackmanb@google.com> Message-Id: <20201203160245.1014867-2-jackmanb@google.com> Mime-Version: 1.0 References: <20201203160245.1014867-1-jackmanb@google.com> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH bpf-next v3 01/14] bpf: x86: Factor out emission of ModR/M for *(reg + off) From: Brendan Jackman To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Yonghong Song , Daniel Borkmann , KP Singh , Florent Revest , linux-kernel@vger.kernel.org, Jann Horn , Brendan Jackman Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net The case for JITing atomics is about to get more complicated. Let's factor out some common code to make the review and result more readable. NB the atomics code doesn't yet use the new helper - a subsequent patch will add its use as a side-effect of other changes. Signed-off-by: Brendan Jackman Change-Id: I1510c7eb0132ff9262fea92ce1839243b6d33372 --- arch/x86/net/bpf_jit_comp.c | 42 +++++++++++++++++++++---------------- 1 file changed, 24 insertions(+), 18 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 796506dcfc42..cc818ed7c2b9 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -681,6 +681,27 @@ static void emit_mov_reg(u8 **pprog, bool is64, u32 dst_reg, u32 src_reg) *pprog = prog; } +/* Emit the suffix (ModR/M etc) for addressing *(ptr_reg + off) and val_reg */ +static void emit_insn_suffix(u8 **pprog, u32 ptr_reg, u32 val_reg, int off) +{ + u8 *prog = *pprog; + int cnt = 0; + + if (is_imm8(off)) { + /* 1-byte signed displacement. + * + * If off == 0 we could skip this and save one extra byte, but + * special case of x86 R13 which always needs an offset is not + * worth the hassle + */ + EMIT2(add_2reg(0x40, ptr_reg, val_reg), off); + } else { + /* 4-byte signed displacement */ + EMIT1_off32(add_2reg(0x80, ptr_reg, val_reg), off); + } + *pprog = prog; +} + /* LDX: dst_reg = *(u8*)(src_reg + off) */ static void emit_ldx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off) { @@ -708,15 +729,7 @@ static void emit_ldx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off) EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B); break; } - /* - * If insn->off == 0 we can save one extra byte, but - * special case of x86 R13 which always needs an offset - * is not worth the hassle - */ - if (is_imm8(off)) - EMIT2(add_2reg(0x40, src_reg, dst_reg), off); - else - EMIT1_off32(add_2reg(0x80, src_reg, dst_reg), off); + emit_insn_suffix(&prog, src_reg, dst_reg, off); *pprog = prog; } @@ -751,10 +764,7 @@ static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off) EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89); break; } - if (is_imm8(off)) - EMIT2(add_2reg(0x40, dst_reg, src_reg), off); - else - EMIT1_off32(add_2reg(0x80, dst_reg, src_reg), off); + emit_insn_suffix(&prog, dst_reg, src_reg, off); *pprog = prog; } @@ -1240,11 +1250,7 @@ st: if (is_imm8(insn->off)) goto xadd; case BPF_STX | BPF_XADD | BPF_DW: EMIT3(0xF0, add_2mod(0x48, dst_reg, src_reg), 0x01); -xadd: if (is_imm8(insn->off)) - EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off); - else - EMIT1_off32(add_2reg(0x80, dst_reg, src_reg), - insn->off); +xadd: emit_modrm_dstoff(&prog, dst_reg, src_reg, insn->off); break; /* call */