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=-9.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 C0D06C282C0 for ; Wed, 23 Jan 2019 06:46:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 87409217F5 for ; Wed, 23 Jan 2019 06:46:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=netronome-com.20150623.gappssmtp.com header.i=@netronome-com.20150623.gappssmtp.com header.b="B/IKQHfn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726880AbfAWGqA (ORCPT ); Wed, 23 Jan 2019 01:46:00 -0500 Received: from mail-qt1-f193.google.com ([209.85.160.193]:34477 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726647AbfAWGp6 (ORCPT ); Wed, 23 Jan 2019 01:45:58 -0500 Received: by mail-qt1-f193.google.com with SMTP id r14so1254885qtp.1 for ; Tue, 22 Jan 2019 22:45:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=3rZXzgyy1JJNg/THmYA5WRz8V3LXcQh3i0TaslLrNkM=; b=B/IKQHfn2FFz9QwBg5YQAoxIXcGjYgqIReUaKehYr34UgHyyVbe51x3Y0bevkcdTwa F6LWImMZxC6pN6spnT/cNZUXv2VxnAaCGscKfSMGElyOuWxITNy1p+T4AnQpHNVYlqI4 hxuGrkLVoP44DnBaHIT+l8QDVLGxHPap4/zOlpOgKIG2cM56KyVJQ1LuGNpIB34ild4F mfpGte+RiWKv0m08DD7NnZVaFW6I4EMrEJCU7eh8cbU3XriuJHfmvDPZN2UtKd0Uivfu LRIJJ9aT3ZgNpDEEStYhave7AFDvnOciZx8l+dbWZrdtnoQmuuc1bnlNpOx32urCgxwH F1wQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=3rZXzgyy1JJNg/THmYA5WRz8V3LXcQh3i0TaslLrNkM=; b=i1DE+Xup8v70I4+GT04nej0pHnJ7I1Q12JPeGtXUkNV/HQN5fAPqLixSnwLUqtosT3 1vts/Ayiq6dD0DveQsnAEyxpxg61hNF4drCUyqwbQTsLFQzGfxwPdPGJA0Z/B+yD99mj LJgg9yaZY1MZf+b2oTIn53iLPvxGxmPAbtuhQQrkgjHR2h4zwkQWHgrBsUxucXjOHyhs +rI44hgHGYma+kUd519p3B8BHuGh5plHJ31A20GVCsp8P2db/bydQvriTB9tlE7Hpuu6 GzrTIWHZyTt0Fhr/DzUlnj/Eu18Fi0tH/YT80YKHIJ3Prooh9V+7ImTQmQZML4uHgwlu /O9w== X-Gm-Message-State: AJcUukd7UNTt2slFAYHECLqFJs3mbs5mipV1eFPjq5lLK7XpyqLo31SC RJ+1ufB0/7QrR2NkmgxlqPayvQ== X-Google-Smtp-Source: ALg8bN7THHCL7virRTxdR8LAc4xaLyXrumFewXJjaS4ePKTig0WN+qrcIOLWBkQcpTF9mUk1Xyl8Gg== X-Received: by 2002:ac8:68d:: with SMTP id f13mr1055475qth.166.1548225956726; Tue, 22 Jan 2019 22:45:56 -0800 (PST) Received: from jkicinski-Precision-T1700.netronome.com ([66.60.152.14]) by smtp.gmail.com with ESMTPSA id k6sm80589046qtk.41.2019.01.22.22.45.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Jan 2019 22:45:56 -0800 (PST) From: Jakub Kicinski To: alexei.starovoitov@gmail.com, daniel@iogearbox.net Cc: yhs@fb.com, netdev@vger.kernel.org, oss-drivers@netronome.com, kafai@fb.com, Jakub Kicinski Subject: [PATCH bpf-next v5 09/12] nfp: bpf: split up the skip flag Date: Tue, 22 Jan 2019 22:45:26 -0800 Message-Id: <20190123064529.13518-10-jakub.kicinski@netronome.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20190123064529.13518-1-jakub.kicinski@netronome.com> References: <20190123064529.13518-1-jakub.kicinski@netronome.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We fail program loading if jump lands on a skipped instruction. This is for historical reasons, it used to be that we only skipped instructions optimized out based on prior context, and therefore the optimization would be buggy if we jumped directly to such instruction (because the context would be skipped by the jump). There are cases where instructions can be skipped without any context, for example there is no point in generating code for: r0 |= 0 We will also soon support dropping dead code, so make the skip logic differentiate between "optimized with preceding context" vs other skip types. Signed-off-by: Jakub Kicinski Reviewed-by: Quentin Monnet --- drivers/net/ethernet/netronome/nfp/bpf/jit.c | 36 ++++++++++--------- drivers/net/ethernet/netronome/nfp/bpf/main.h | 9 +++-- 2 files changed, 26 insertions(+), 19 deletions(-) diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c index 323587dee498..054382b9cbe6 100644 --- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c +++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c @@ -1266,7 +1266,7 @@ wrp_alu64_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, u64 imm = insn->imm; /* sign extend */ if (skip) { - meta->skip = true; + meta->flags |= FLAG_INSN_SKIP_NOOP; return 0; } @@ -1296,7 +1296,7 @@ wrp_alu32_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, const struct bpf_insn *insn = &meta->insn; if (skip) { - meta->skip = true; + meta->flags |= FLAG_INSN_SKIP_NOOP; return 0; } @@ -3395,7 +3395,7 @@ static int nfp_fixup_branches(struct nfp_prog *nfp_prog) int err; list_for_each_entry(meta, &nfp_prog->insns, l) { - if (meta->skip) + if (meta->flags & FLAG_INSN_SKIP_MASK) continue; if (BPF_CLASS(meta->insn.code) != BPF_JMP) continue; @@ -3439,7 +3439,7 @@ static int nfp_fixup_branches(struct nfp_prog *nfp_prog) jmp_dst = meta->jmp_dst; - if (jmp_dst->skip) { + if (jmp_dst->flags & FLAG_INSN_SKIP_PREC_DEPENDENT) { pr_err("Branch landing on removed instruction!!\n"); return -ELOOP; } @@ -3689,7 +3689,7 @@ static int nfp_translate(struct nfp_prog *nfp_prog) return nfp_prog->error; } - if (meta->skip) { + if (meta->flags & FLAG_INSN_SKIP_MASK) { nfp_prog->n_translated++; continue; } @@ -3737,10 +3737,10 @@ static void nfp_bpf_opt_reg_init(struct nfp_prog *nfp_prog) /* Programs start with R6 = R1 but we ignore the skb pointer */ if (insn.code == (BPF_ALU64 | BPF_MOV | BPF_X) && insn.src_reg == 1 && insn.dst_reg == 6) - meta->skip = true; + meta->flags |= FLAG_INSN_SKIP_PREC_DEPENDENT; /* Return as soon as something doesn't match */ - if (!meta->skip) + if (!(meta->flags & FLAG_INSN_SKIP_MASK)) return; } } @@ -3755,7 +3755,7 @@ static void nfp_bpf_opt_neg_add_sub(struct nfp_prog *nfp_prog) list_for_each_entry(meta, &nfp_prog->insns, l) { struct bpf_insn insn = meta->insn; - if (meta->skip) + if (meta->flags & FLAG_INSN_SKIP_MASK) continue; if (BPF_CLASS(insn.code) != BPF_ALU && @@ -3829,7 +3829,7 @@ static void nfp_bpf_opt_ld_mask(struct nfp_prog *nfp_prog) if (meta2->flags & FLAG_INSN_IS_JUMP_DST) continue; - meta2->skip = true; + meta2->flags |= FLAG_INSN_SKIP_PREC_DEPENDENT; } } @@ -3869,8 +3869,8 @@ static void nfp_bpf_opt_ld_shift(struct nfp_prog *nfp_prog) meta3->flags & FLAG_INSN_IS_JUMP_DST) continue; - meta2->skip = true; - meta3->skip = true; + meta2->flags |= FLAG_INSN_SKIP_PREC_DEPENDENT; + meta3->flags |= FLAG_INSN_SKIP_PREC_DEPENDENT; } } @@ -4065,7 +4065,8 @@ static void nfp_bpf_opt_ldst_gather(struct nfp_prog *nfp_prog) } head_ld_meta->paired_st = &head_st_meta->insn; - head_st_meta->skip = true; + head_st_meta->flags |= + FLAG_INSN_SKIP_PREC_DEPENDENT; } else { head_ld_meta->ldst_gather_len = 0; } @@ -4098,8 +4099,8 @@ static void nfp_bpf_opt_ldst_gather(struct nfp_prog *nfp_prog) head_ld_meta = meta1; head_st_meta = meta2; } else { - meta1->skip = true; - meta2->skip = true; + meta1->flags |= FLAG_INSN_SKIP_PREC_DEPENDENT; + meta2->flags |= FLAG_INSN_SKIP_PREC_DEPENDENT; } head_ld_meta->ldst_gather_len += BPF_LDST_BYTES(ld); @@ -4124,7 +4125,7 @@ static void nfp_bpf_opt_pkt_cache(struct nfp_prog *nfp_prog) if (meta->flags & FLAG_INSN_IS_JUMP_DST) cache_avail = false; - if (meta->skip) + if (meta->flags & FLAG_INSN_SKIP_MASK) continue; insn = &meta->insn; @@ -4210,7 +4211,7 @@ static void nfp_bpf_opt_pkt_cache(struct nfp_prog *nfp_prog) } list_for_each_entry(meta, &nfp_prog->insns, l) { - if (meta->skip) + if (meta->flags & FLAG_INSN_SKIP_MASK) continue; if (is_mbpf_load_pkt(meta) && !meta->ldst_gather_len) { @@ -4246,7 +4247,8 @@ static int nfp_bpf_replace_map_ptrs(struct nfp_prog *nfp_prog) u32 id; nfp_for_each_insn_walk2(nfp_prog, meta1, meta2) { - if (meta1->skip || meta2->skip) + if (meta1->flags & FLAG_INSN_SKIP_MASK || + meta2->flags & FLAG_INSN_SKIP_MASK) continue; if (meta1->insn.code != (BPF_LD | BPF_IMM | BPF_DW) || diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.h b/drivers/net/ethernet/netronome/nfp/bpf/main.h index 941277936475..40291aedd895 100644 --- a/drivers/net/ethernet/netronome/nfp/bpf/main.h +++ b/drivers/net/ethernet/netronome/nfp/bpf/main.h @@ -243,6 +243,13 @@ struct nfp_bpf_reg_state { #define FLAG_INSN_IS_JUMP_DST BIT(0) #define FLAG_INSN_IS_SUBPROG_START BIT(1) #define FLAG_INSN_PTR_CALLER_STACK_FRAME BIT(2) +/* Instruction is pointless, noop even on its own */ +#define FLAG_INSN_SKIP_NOOP BIT(3) +/* Instruction is optimized out based on preceding instructions */ +#define FLAG_INSN_SKIP_PREC_DEPENDENT BIT(4) + +#define FLAG_INSN_SKIP_MASK (FLAG_INSN_SKIP_NOOP | \ + FLAG_INSN_SKIP_PREC_DEPENDENT) /** * struct nfp_insn_meta - BPF instruction wrapper @@ -271,7 +278,6 @@ struct nfp_bpf_reg_state { * @n: eBPF instruction number * @flags: eBPF instruction extra optimization flags * @subprog_idx: index of subprogram to which the instruction belongs - * @skip: skip this instruction (optimized out) * @double_cb: callback for second part of the instruction * @l: link on nfp_prog->insns list */ @@ -319,7 +325,6 @@ struct nfp_insn_meta { unsigned short n; unsigned short flags; unsigned short subprog_idx; - bool skip; instr_cb_t double_cb; struct list_head l; -- 2.19.2