From mboxrd@z Thu Jan 1 00:00:00 1970 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=unavailable 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 068FAC4361B for ; Tue, 15 Dec 2020 12:24:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C99DE224D2 for ; Tue, 15 Dec 2020 12:24:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729220AbgLOMX4 (ORCPT ); Tue, 15 Dec 2020 07:23:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729158AbgLOMTs (ORCPT ); Tue, 15 Dec 2020 07:19:48 -0500 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E10C2C061285 for ; Tue, 15 Dec 2020 04:18:30 -0800 (PST) Received: by mail-qk1-x749.google.com with SMTP id e68so15148751qkd.3 for ; Tue, 15 Dec 2020 04:18:30 -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=awDIGdsuaCR5uomtG5MWC9cz+3R1uJ7OWj5HtB8gNQs=; b=i/4nuK0KDwi4/rh/U9NQak7siySEFB/RjHCUJXuSN7oGsljJ3AJ/VbfxDdORfMwddg PJHuurEsTsgg7+U6JxKnT+jmtop4wgYNGsfyJDmN3JHUhQ7JspbOI2QEKxvLinLxctax bXlvjZ288SsRivo7KuAMZsHN+jHrtp3GmEJV8GkOcPlpIbMia3vQexmmWXqPDLsrVDxv zHDZe8ado1IjFTHVeSl3BGXwWfk3WzEsm/gDsywnww3abKsPKwbyqjuvU8Xkw+5z395n WfbnbDv4pXr2A+MeE9rbqWcPY5xf7nwRQqs+oJ5OnpjQz2f8GbksVkNb0sdlfcGh5rGI NrCg== 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=awDIGdsuaCR5uomtG5MWC9cz+3R1uJ7OWj5HtB8gNQs=; b=ZEUT0Nx5qLDaYtG0LgT+9T+jtlN1aqkO/qbBHbffoGtQ32Dh/Ba7f3vCu+dIuCPSzJ f7hMQ3qcTz7nYqXKaPMH464Pi7+QMT6hT1G3zX/2aVtE+osMG9+4zI+o7a3lDrkygUN/ LoqhpPCXTPErcYCRqUBJbsXECIne7jDyrfW8uivaOAkNXwnVmz63Q10l5mxUp8559H1C 9xAb8eCdr/7M7Waiy9YaT4rLiJgRZItG93XXw+TRm1tQPEgzlL44wlqb9tfjFnK8C5LW SBPvrOrkKh9wjTD+w8MGq0gyfQ+nXiJR1KfFoZRTJf1I/AijtLj7J7IuKYSwG1CJrbxr GxBA== X-Gm-Message-State: AOAM533LcBaEwdmMJR0E9Q2P9OlKfxY4SHq+yUaWJBX5QTOBeQheELsc TfeChCIqbfjrMi9VNQ10LQeO+ytPDxuuvQ== X-Google-Smtp-Source: ABdhPJwVCCkz9zLIK9yn6vvrEt5B6G7vs29ttTel/HJTmDamy7Ue0D+NORJsc4iYEroz30OS2o/JkfyB35Lkcw== 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:a05:6214:768:: with SMTP id f8mr37249328qvz.1.1608034707105; Tue, 15 Dec 2020 04:18:27 -0800 (PST) Date: Tue, 15 Dec 2020 12:18:07 +0000 In-Reply-To: <20201215121816.1048557-1-jackmanb@google.com> Message-Id: <20201215121816.1048557-4-jackmanb@google.com> Mime-Version: 1.0 References: <20201215121816.1048557-1-jackmanb@google.com> X-Mailer: git-send-email 2.29.2.684.gfbc64c5ab5-goog Subject: [PATCH bpf-next v5 02/11] bpf: x86: Factor out emission of REX byte From: Brendan Jackman To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , KP Singh , Florent Revest , linux-kernel@vger.kernel.org, Brendan Jackman , John Fastabend Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The JIT case for encoding atomic ops is about to get more complicated. In order to make the review & resulting code easier, let's factor out some shared helpers. Signed-off-by: Brendan Jackman Acked-by: John Fastabend --- arch/x86/net/bpf_jit_comp.c | 39 ++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 16 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 30526776fa78..f15c93275a18 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -702,6 +702,21 @@ static void emit_insn_suffix(u8 **pprog, u32 ptr_reg, u32 val_reg, int off) *pprog = prog; } +/* + * Emit a REX byte if it will be necessary to address these registers + */ +static void maybe_emit_mod(u8 **pprog, u32 dst_reg, u32 src_reg, bool is64) +{ + u8 *prog = *pprog; + int cnt = 0; + + if (is64) + EMIT1(add_2mod(0x48, dst_reg, src_reg)); + else if (is_ereg(dst_reg) || is_ereg(src_reg)) + EMIT1(add_2mod(0x40, dst_reg, src_reg)); + *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) { @@ -854,10 +869,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, case BPF_OR: b2 = 0x09; break; case BPF_XOR: b2 = 0x31; break; } - if (BPF_CLASS(insn->code) == BPF_ALU64) - EMIT1(add_2mod(0x48, dst_reg, src_reg)); - else if (is_ereg(dst_reg) || is_ereg(src_reg)) - EMIT1(add_2mod(0x40, dst_reg, src_reg)); + maybe_emit_mod(&prog, dst_reg, src_reg, + BPF_CLASS(insn->code) == BPF_ALU64); EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg)); break; @@ -1302,20 +1315,16 @@ st: if (is_imm8(insn->off)) case BPF_JMP32 | BPF_JSGE | BPF_X: case BPF_JMP32 | BPF_JSLE | BPF_X: /* cmp dst_reg, src_reg */ - if (BPF_CLASS(insn->code) == BPF_JMP) - EMIT1(add_2mod(0x48, dst_reg, src_reg)); - else if (is_ereg(dst_reg) || is_ereg(src_reg)) - EMIT1(add_2mod(0x40, dst_reg, src_reg)); + maybe_emit_mod(&prog, dst_reg, src_reg, + BPF_CLASS(insn->code) == BPF_JMP); EMIT2(0x39, add_2reg(0xC0, dst_reg, src_reg)); goto emit_cond_jmp; case BPF_JMP | BPF_JSET | BPF_X: case BPF_JMP32 | BPF_JSET | BPF_X: /* test dst_reg, src_reg */ - if (BPF_CLASS(insn->code) == BPF_JMP) - EMIT1(add_2mod(0x48, dst_reg, src_reg)); - else if (is_ereg(dst_reg) || is_ereg(src_reg)) - EMIT1(add_2mod(0x40, dst_reg, src_reg)); + maybe_emit_mod(&prog, dst_reg, src_reg, + BPF_CLASS(insn->code) == BPF_JMP); EMIT2(0x85, add_2reg(0xC0, dst_reg, src_reg)); goto emit_cond_jmp; @@ -1351,10 +1360,8 @@ st: if (is_imm8(insn->off)) case BPF_JMP32 | BPF_JSLE | BPF_K: /* test dst_reg, dst_reg to save one extra byte */ if (imm32 == 0) { - if (BPF_CLASS(insn->code) == BPF_JMP) - EMIT1(add_2mod(0x48, dst_reg, dst_reg)); - else if (is_ereg(dst_reg)) - EMIT1(add_2mod(0x40, dst_reg, dst_reg)); + maybe_emit_mod(&prog, dst_reg, dst_reg, + BPF_CLASS(insn->code) == BPF_JMP); EMIT2(0x85, add_2reg(0xC0, dst_reg, dst_reg)); goto emit_cond_jmp; } -- 2.29.2.684.gfbc64c5ab5-goog