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 DAED9C4167B for ; Mon, 7 Dec 2020 16:09:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D1C923731 for ; Mon, 7 Dec 2020 16:09:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727550AbgLGQJD (ORCPT ); Mon, 7 Dec 2020 11:09:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726790AbgLGQJB (ORCPT ); Mon, 7 Dec 2020 11:09:01 -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 A3F43C06179C for ; Mon, 7 Dec 2020 08:08:15 -0800 (PST) Received: by mail-qk1-x749.google.com with SMTP id s9so12869444qks.2 for ; Mon, 07 Dec 2020 08:08:15 -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=j/coOO3IKOdSaOfJ3wqiBZ3KaCdyY0hEgLU+r80vPUs=; b=I36vtmcnTyxFYOmiqiPgxadSYWAsjO+op4FfMTkVic9jl/uEocEHAPIH99J28rHU+H J8VyK7M/xxdMnhFpOYhDOCj3bqO276nXazmvWwgRJTZaUokleuShogPNoYRi4I35attT y+ZeQqavoOLEBWNZ0hUbDw2vmx+yjygEf537iqsFwfWsvJJ+TJigkvAexKIQ7VWuXlxP 16L4CAeoCTXv9hiNXOgh7Nyd4JhRoS/MrJPr45MkTs8gE4L530gVs1lVWcNX5+NcMAuv CEHMidrbj1J5sXNbcStcb4SYQO3pGMkXkbNJws6pmcK0ycL8nV1k8CMhNqK+vJK23uMa oqiw== 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=j/coOO3IKOdSaOfJ3wqiBZ3KaCdyY0hEgLU+r80vPUs=; b=GiIMz9zxGwwOglXtbjI1KW1JK6m0EfdMEVA0HCiLbqjD3m5lyBsWB7zU9vtbDOXOp7 jOEJ2ijed8edpielrXtPceafHEHLH8U8A/hDaN26EoaWyL491RyChYpYcsGlXbMmEi// bK1IpUUuSvAL+weQutslyu43Xqx+AsW7Jn3CG169NZj2gxlqZ5tkfrxAnyb0E84k4DNe wqmismZBHXriLZXQPUFDwY/znfNx5yOCeZG2CKY5tw2dsHVgv3QUHme/TkI53W0yAjS3 NdMZ7CsP1mGIP2uYTtwBmBuARejJZ0yskEu8s8LEQw2zdkO0gu2U5Ug1WpzdWh/5n7bg jeIQ== X-Gm-Message-State: AOAM530pPSoei6EUMzEEM0Xg4HyBWiFTIIvUp3NqUKYDHjw9Ou3J1HqR Fe+9s0TPHToV/Py4zpbl4WAfAGBA8Rupcw== X-Google-Smtp-Source: ABdhPJzQjoDPtmDlyR8EWmHh3eOfPSgXNrm27/UV/GIsoB4gO7SktrghBFimIdbXyj6QM1d5iGb/Lyxee7H+uA== 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:a05:6214:10c6:: with SMTP id r6mr16980502qvs.44.1607357294782; Mon, 07 Dec 2020 08:08:14 -0800 (PST) Date: Mon, 7 Dec 2020 16:07:24 +0000 In-Reply-To: <20201207160734.2345502-1-jackmanb@google.com> Message-Id: <20201207160734.2345502-2-jackmanb@google.com> Mime-Version: 1.0 References: <20201207160734.2345502-1-jackmanb@google.com> X-Mailer: git-send-email 2.29.2.576.ga3fc446d84-goog Subject: [PATCH bpf-next v4 01/11] 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 */ -- 2.29.2.576.ga3fc446d84-goog