From patchwork Thu Jan 14 18:17:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brendan Jackman X-Patchwork-Id: 12020577 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=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 2E829C433E0 for ; Thu, 14 Jan 2021 18:19:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBE4E23A50 for ; Thu, 14 Jan 2021 18:19:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729348AbhANSSu (ORCPT ); Thu, 14 Jan 2021 13:18:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729345AbhANSSt (ORCPT ); Thu, 14 Jan 2021 13:18:49 -0500 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5413FC0613D3 for ; Thu, 14 Jan 2021 10:18:09 -0800 (PST) Received: by mail-qv1-xf49.google.com with SMTP id f7so5266148qvr.4 for ; Thu, 14 Jan 2021 10:18:09 -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=4StJvEPcqpOoMaFQqXp2l4E4gqPLXrwP2qT6WBxKOzM=; b=GobCPeYowh3r/lLNPJLitXo++prm+HDGITq517VlpQwWxv+IKVbVnnse0Jw9P4pWKj uTaVx7oEQ/QvfRvlJD8a4w1UJD6rqIFwCsglox0IyRzeh7p6ou2NhSNr6eLh8JIdOu/H i+6ehi/Mlf6qSdLWZNtpNBy7Tq8uhLUa5n5cfRf4KK/YncdZzTDpg7f1pWwBqJlh4XZE wK3l3NTW/Aq0GZTw3cF5i4RIzjJyrzbOhJyi2QVmySeBwpicPt1+XQujMxTFvaF5YNGs E0alYo1fhFIeiKC8rKgPPGmsxvZYh3OteW+N3JE29e1XPOnmtXHICScigIQgJXXHo63K e1qg== 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=4StJvEPcqpOoMaFQqXp2l4E4gqPLXrwP2qT6WBxKOzM=; b=lpUKsknMpzdXDHUcyDjGxUFY3Ustdj4gTmOsr9bWj0n6wKiTymcsVkrRzvKHfIARy+ hRD+tW5VYKFBuO/TmQu1yLEwzJb2oHHdPDeKgwj+lnOoDiYp0VtdgKa7pfLfD4XaHmax YnJkolonaq1pm0xZIn/TPyU/yvGwAAjrDRDd/6voIBzbTJ5HUJt7q7b1w01OCKd8EABD KK6CPs9oF2vb0/zpB4/BGyA77puTwGzZR3exC3NvkWm1BpIUqEfm95j7Lr657jU3oxzk 8Jvg7vtmBvjKAFKQkyTsuos+86wxkPqXzZeEHhT0+KBXq4pho2P2yCxFjYrA6dwEyZfh kXvg== X-Gm-Message-State: AOAM531oHQ3qxSkvUgQ0il3AMuNTLqOdt3t6zad5bmbwZ3evtfByFzFw jGgDKL6drT1BHYcXsD8xamALzNbeDq9J+En0XzxAZLUfGyITLPrGWkwF+s1+UbTdcziPhs+0Kzl B4HF/oxDM3OncNlF3i0XCvdYMGYYfwDeI4Ot3882EwRzzSEePIw2MM/U7GHcUjPM= X-Google-Smtp-Source: ABdhPJygvCFqDDlF4ox29jIpa6X40Y6F/9plae/kqJpo7jaYHxrswA8ZOl2XU+Gf4hWMwhNTnYQ+RbO2hzxzKA== 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:a05:6214:727:: with SMTP id c7mr8439214qvz.22.1610648288369; Thu, 14 Jan 2021 10:18:08 -0800 (PST) Date: Thu, 14 Jan 2021 18:17:41 +0000 In-Reply-To: <20210114181751.768687-1-jackmanb@google.com> Message-Id: <20210114181751.768687-2-jackmanb@google.com> Mime-Version: 1.0 References: <20210114181751.768687-1-jackmanb@google.com> X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH bpf-next v7 01/11] bpf: x86: Factor out emission of ModR/M for *(reg + off) From: Brendan Jackman To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , KP Singh , Florent Revest , linux-kernel@vger.kernel.org, " =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= " , John Fastabend , Yonghong Song , 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. Acked-by: John Fastabend Signed-off-by: Brendan Jackman --- arch/x86/net/bpf_jit_comp.c | 43 +++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 18 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 796506dcfc42..30526776fa78 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 +1250,8 @@ 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 */