From patchwork Tue Dec 15 12:18:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brendan Jackman X-Patchwork-Id: 11974743 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 CA9F0C2BB9A for ; Tue, 15 Dec 2020 12:27:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F7D92255F for ; Tue, 15 Dec 2020 12:27:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729211AbgLOMTN (ORCPT ); Tue, 15 Dec 2020 07:19:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729206AbgLOMTE (ORCPT ); Tue, 15 Dec 2020 07:19:04 -0500 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3FF4C0617B0 for ; Tue, 15 Dec 2020 04:18:23 -0800 (PST) Received: by mail-qk1-x74a.google.com with SMTP id u67so15096661qkd.6 for ; Tue, 15 Dec 2020 04:18:23 -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=EFUqTun0uiztqF8e8qrxxBNJTBQ8iaau+8b6EYHnDrA=; b=ANFVyiy342mU1MuLFdCSKtfnQX1LJ28tYdHdqAmc9J1VZOsC0xhaTukZRr7aQLVQI4 98YwOtWkH/78rOQYhIGTCAHQhdDJrppRdHh1cBTQJlSly0UdhDEgIQGXooldNz2S6n7x HZqFs/TorfbJL8vy9wZdIA3MJQMYGYao4aiB/XYc850cDH/67ttXr6zo7WNJ3H37xSRa PqjshekO2BLx+sex0vOTqHGK+Mt71feRyUMjML+SkTi5zmfvB1zQYBkb2VcZHtpjyS/H aFgriSu7vkWgnr7/aGgTE0493VcSGBAlAhgjetkJD6PQBZadIaaxKADGoLJ5WJuvq+h3 xagA== 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=EFUqTun0uiztqF8e8qrxxBNJTBQ8iaau+8b6EYHnDrA=; b=RVNWsbH4s/X8N8NVaODnqN13/k8Or5GL8YQUnJ4fAiW6gpylIRTUcKDitfaIi6UHdT XETtwLlNk2DVBfh1ltmh4e7W/SknhQkyGFaptbpsq+Z9Jv7cDcWaBYkzAnGLdhvnMw5V AXh+G7EYmjNEXoGscDYF52wngtywFy5uvDOUOoiEWLH73AF4WK3f9tAJsmhjb+S5YkQm ZuATQcH+6eVDDdTp3vqvpPPqsjRqQ/ZWLoRHRKBDaKZxfhyE9QhXIQaWPBXuQM4m/MeK gIDqeRqHkaZugJszbCmdPGc0DcJF63ZEvPLQLhiZb7m9jdFtQvCeXm8412btweBUMBmx tezA== X-Gm-Message-State: AOAM533YmdfgjPhJfCUDEz4A8CQZ74oaHPwI9shSNFD8TmSNt1DUHwt0 hg5GGlLAOdv7cXkxuPT840gVxW2w0J3LZufY2e6wFgCYsLnxkbTaBUwtHJa+siOUU4SJLnqWJ9H mxTRrVSkOCSetnM7UEjUsXGa41px7ernRkZXi8rnBPobuUyk5J2R8VOW7WWBd7L4= X-Google-Smtp-Source: ABdhPJzyP/jH3oqivt3T11x13be/qwXU5t9VDpvGWhM3lm2gNvgY4rntDqlf8ENgeZFN0Gx9y0Xv/XqMKqaq0g== 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:ad4:49cd:: with SMTP id j13mr1815913qvy.5.1608034702652; Tue, 15 Dec 2020 04:18:22 -0800 (PST) Date: Tue, 15 Dec 2020 12:18:05 +0000 In-Reply-To: <20201215121816.1048557-1-jackmanb@google.com> Message-Id: <20201215121816.1048557-2-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 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, Brendan Jackman , John Fastabend 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 */