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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 45327C74A35 for ; Thu, 11 Jul 2019 11:59:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0522921537 for ; Thu, 11 Jul 2019 11:59:17 +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="hkmlNV2G" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727974AbfGKL7R (ORCPT ); Thu, 11 Jul 2019 07:59:17 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:44081 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728198AbfGKL7R (ORCPT ); Thu, 11 Jul 2019 07:59:17 -0400 Received: by mail-wr1-f67.google.com with SMTP id p17so5966305wrf.11 for ; Thu, 11 Jul 2019 04:59:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=references:user-agent:from:to:cc:subject:in-reply-to:date :message-id:mime-version; bh=5vu72Pa+XWsA3e7pdSb3CfwSv7O8asY1FTsoovcZqqk=; b=hkmlNV2GBd8+/pJPC+lKCOCvPbjB+R/bJYeo79Tdtc0ATDPcH7l+Yfz4W5+m0qBiaj jYQU8/RH36FdRnhTStebAPlL5JWBNSdw/kDHfYMVpFHF3taMv3UlwHT4leejodTg5Jr1 KlxH669NUD/mEOCoHAI6tn4VA3xgNGmMJT4W6bUcX7LnKjHTgxFfHP5POt53DztUP5PV UBNh7MXrP5Tngw+v+Rz0J2tdgzhmB4ePZF/Jt4xYLGZHFIckAZZZUMzBc7eIBXS82PBX n3Cu7E9uJ9U5aYDcEVhyu5N6nwVCUpGsi+Noj1KFK12DgvQGXXTWerpqAalFXZDv/umC fM+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:date:message-id:mime-version; bh=5vu72Pa+XWsA3e7pdSb3CfwSv7O8asY1FTsoovcZqqk=; b=dWN8cy51FbndbzE3XKfQG+3vv9vhnq/y7kj6RPAlicCTHEiUvlbYlAusmpeRt0jl+m UPJAI3SZpc+e3PdI9Q36/aesu9vsHae2sU11HwevmUUO+vqi9xvNvay3x5Ip0Nvtzhrp GZsbVxiabrj5l6pGp8DnA7/lDB2L7CrIxWrXVoF8J6xvyzNsRIsvntWkeG6DyRQ04Eks C8G5CJoLWx47o/2z6pQ3feUZUiqz8QmYaHVVexRdXHrYPzR7vE5rXQPKj31CJFPHMZhM lF/wxUGxyP0aQDpkE6ViN0CE6XVwwYLDYZj9XBRfiu4yeWa7Lx+VLNZWaW7FkNF1nNwF dSGg== X-Gm-Message-State: APjAAAXD/vcbcdXCsFHjGOrowQElYPC5d7GZ3EJihdUrfzBLRySXwMgv vbZMxHNs/tVk7yrZLAKB6LPgug== X-Google-Smtp-Source: APXvYqwyv17KUcCwDg2uwOLKfzKaFEJTxfy0XN/Gczu9/uuEoDLNSSsyUj3ushp5tBc8v/nro+sz+g== X-Received: by 2002:adf:ec49:: with SMTP id w9mr4630060wrn.303.1562846353921; Thu, 11 Jul 2019 04:59:13 -0700 (PDT) Received: from LAPTOP-V3S7NLPL ([217.38.71.146]) by smtp.gmail.com with ESMTPSA id q1sm4648133wmq.25.2019.07.11.04.59.13 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 11 Jul 2019 04:59:13 -0700 (PDT) References: <1562275611-31790-1-git-send-email-jiong.wang@netronome.com> <1562275611-31790-3-git-send-email-jiong.wang@netronome.com> User-agent: mu4e 0.9.18; emacs 25.2.2 From: Jiong Wang To: Andrii Nakryiko Cc: Jiong Wang , Alexei Starovoitov , Daniel Borkmann , Edward Cree , "Naveen N. Rao" , Andrii Nakryiko , Jakub Kicinski , bpf , Networking , oss-drivers@netronome.com Subject: Re: [oss-drivers] Re: [RFC bpf-next 2/8] bpf: extend list based insn patching infra to verification layer In-reply-to: Date: Thu, 11 Jul 2019 12:59:10 +0100 Message-ID: <87o920235d.fsf@netronome.com> MIME-Version: 1.0 Content-Type: text/plain Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Andrii Nakryiko writes: > On Thu, Jul 4, 2019 at 2:32 PM Jiong Wang wrote: >> >> Verification layer also needs to handle auxiliar info as well as adjusting >> subprog start. >> >> At this layer, insns inside patch buffer could be jump, but they should >> have been resolved, meaning they shouldn't jump to insn outside of the >> patch buffer. Lineration function for this layer won't touch insns inside >> patch buffer. >> >> Adjusting subprog is finished along with adjusting jump target when the >> input will cover bpf to bpf call insn, re-register subprog start is cheap. >> But adjustment when there is insn deleteion is not considered yet. >> >> Signed-off-by: Jiong Wang >> --- >> kernel/bpf/verifier.c | 150 ++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 150 insertions(+) >> >> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c >> index a2e7637..2026d64 100644 >> --- a/kernel/bpf/verifier.c >> +++ b/kernel/bpf/verifier.c >> @@ -8350,6 +8350,156 @@ static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env) >> } >> } >> >> +/* Linearize bpf list insn to array (verifier layer). */ >> +static struct bpf_verifier_env * >> +verifier_linearize_list_insn(struct bpf_verifier_env *env, >> + struct bpf_list_insn *list) > > It's unclear why this returns env back? It's not allocating a new env, > so it's weird and unnecessary. Just return error code. The reason is I was thinking we have two layers in BPF, the core and the verifier. For core layer (the relevant file is core.c), when doing patching, the input is insn list and bpf_prog, the linearization should linearize the insn list into insn array, and also whatever others affect inside bpf_prog due to changing on insns, for example line info inside prog->aux. So the return value is bpf_prog for core layer linearization hook. For verifier layer, it is similar, but the context if bpf_verifier_env, the linearization hook should linearize the insn list, and also those affected inside env, for example bpf_insn_aux_data, so the return value is bpf_verifier_env, meaning returning an updated verifier context (bpf_verifier_env) after insn list linearization. Make sense? Regards, Jiong > >> +{ >> + u32 *idx_map, idx, orig_cnt, fini_cnt = 0; >> + struct bpf_subprog_info *new_subinfo; >> + struct bpf_insn_aux_data *new_data; >> + struct bpf_prog *prog = env->prog; >> + struct bpf_verifier_env *ret_env; >> + struct bpf_insn *insns, *insn; >> + struct bpf_list_insn *elem; >> + int ret; >> + >> + /* Calculate final size. */ >> + for (elem = list; elem; elem = elem->next) >> + if (!(elem->flag & LIST_INSN_FLAG_REMOVED)) >> + fini_cnt++; >> + >> + orig_cnt = prog->len; >> + insns = prog->insnsi; >> + /* If prog length remains same, nothing else to do. */ >> + if (fini_cnt == orig_cnt) { >> + for (insn = insns, elem = list; elem; elem = elem->next, insn++) >> + *insn = elem->insn; >> + return env; >> + } >> + /* Realloc insn buffer when necessary. */ >> + if (fini_cnt > orig_cnt) >> + prog = bpf_prog_realloc(prog, bpf_prog_size(fini_cnt), >> + GFP_USER); >> + if (!prog) >> + return ERR_PTR(-ENOMEM); >> + insns = prog->insnsi; >> + prog->len = fini_cnt; >> + ret_env = env; >> + >> + /* idx_map[OLD_IDX] = NEW_IDX */ >> + idx_map = kvmalloc(orig_cnt * sizeof(u32), GFP_KERNEL); >> + if (!idx_map) >> + return ERR_PTR(-ENOMEM); >> + memset(idx_map, 0xff, orig_cnt * sizeof(u32)); >> + >> + /* Use the same alloc method used when allocating env->insn_aux_data. */ >> + new_data = vzalloc(array_size(sizeof(*new_data), fini_cnt)); >> + if (!new_data) { >> + kvfree(idx_map); >> + return ERR_PTR(-ENOMEM); >> + } >> + >> + /* Copy over insn + calculate idx_map. */ >> + for (idx = 0, elem = list; elem; elem = elem->next) { >> + int orig_idx = elem->orig_idx - 1; >> + >> + if (orig_idx >= 0) { >> + idx_map[orig_idx] = idx; >> + >> + if (elem->flag & LIST_INSN_FLAG_REMOVED) >> + continue; >> + >> + new_data[idx] = env->insn_aux_data[orig_idx]; >> + >> + if (elem->flag & LIST_INSN_FLAG_PATCHED) >> + new_data[idx].zext_dst = >> + insn_has_def32(env, &elem->insn); >> + } else { >> + new_data[idx].seen = true; >> + new_data[idx].zext_dst = insn_has_def32(env, >> + &elem->insn); >> + } >> + insns[idx++] = elem->insn; >> + } >> + >> + new_subinfo = kvzalloc(sizeof(env->subprog_info), GFP_KERNEL); >> + if (!new_subinfo) { >> + kvfree(idx_map); >> + vfree(new_data); >> + return ERR_PTR(-ENOMEM); >> + } >> + memcpy(new_subinfo, env->subprog_info, sizeof(env->subprog_info)); >> + memset(env->subprog_info, 0, sizeof(env->subprog_info)); >> + env->subprog_cnt = 0; >> + env->prog = prog; >> + ret = add_subprog(env, 0); >> + if (ret < 0) { >> + ret_env = ERR_PTR(ret); >> + goto free_all_ret; >> + } >> + /* Relocate jumps using idx_map. >> + * old_dst = jmp_insn.old_target + old_pc + 1; >> + * new_dst = idx_map[old_dst] = jmp_insn.new_target + new_pc + 1; >> + * jmp_insn.new_target = new_dst - new_pc - 1; >> + */ >> + for (idx = 0, elem = list; elem; elem = elem->next) { >> + int orig_idx = elem->orig_idx; >> + >> + if (elem->flag & LIST_INSN_FLAG_REMOVED) >> + continue; >> + if ((elem->flag & LIST_INSN_FLAG_PATCHED) || !orig_idx) { >> + idx++; >> + continue; >> + } >> + >> + ret = bpf_jit_adj_imm_off(&insns[idx], orig_idx - 1, idx, >> + idx_map); >> + if (ret < 0) { >> + ret_env = ERR_PTR(ret); >> + goto free_all_ret; >> + } >> + /* Recalculate subprog start as we are at bpf2bpf call insn. */ >> + if (ret > 0) { >> + ret = add_subprog(env, idx + insns[idx].imm + 1); >> + if (ret < 0) { >> + ret_env = ERR_PTR(ret); >> + goto free_all_ret; >> + } >> + } >> + idx++; >> + } >> + if (ret < 0) { >> + ret_env = ERR_PTR(ret); >> + goto free_all_ret; >> + } >> + >> + env->subprog_info[env->subprog_cnt].start = fini_cnt; >> + for (idx = 0; idx <= env->subprog_cnt; idx++) >> + new_subinfo[idx].start = env->subprog_info[idx].start; >> + memcpy(env->subprog_info, new_subinfo, sizeof(env->subprog_info)); >> + >> + /* Adjust linfo. >> + * FIXME: no support for insn removal at the moment. >> + */ >> + if (prog->aux->nr_linfo) { >> + struct bpf_line_info *linfo = prog->aux->linfo; >> + u32 nr_linfo = prog->aux->nr_linfo; >> + >> + for (idx = 0; idx < nr_linfo; idx++) >> + linfo[idx].insn_off = idx_map[linfo[idx].insn_off]; >> + } >> + vfree(env->insn_aux_data); >> + env->insn_aux_data = new_data; >> + goto free_mem_list_ret; >> +free_all_ret: >> + vfree(new_data); >> +free_mem_list_ret: >> + kvfree(new_subinfo); >> + kvfree(idx_map); >> + return ret_env; >> +} >> + >> static int opt_remove_dead_code(struct bpf_verifier_env *env) >> { >> struct bpf_insn_aux_data *aux_data = env->insn_aux_data; >> -- >> 2.7.4 >>