From patchwork Sat Apr 17 03:32:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 12209501 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 BF542C43460 for ; Sat, 17 Apr 2021 03:33:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A23706115B for ; Sat, 17 Apr 2021 03:33:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235778AbhDQDeB (ORCPT ); Fri, 16 Apr 2021 23:34:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235632AbhDQDdw (ORCPT ); Fri, 16 Apr 2021 23:33:52 -0400 Received: from mail-pf1-x434.google.com (mail-pf1-x434.google.com [IPv6:2607:f8b0:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B566C061342; Fri, 16 Apr 2021 20:32:44 -0700 (PDT) Received: by mail-pf1-x434.google.com with SMTP id g16so6286675pfq.5; Fri, 16 Apr 2021 20:32:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=KBk3bK4feaNc3+lvwrD6wznDNxRkOBFpu408+U2igpg=; b=l8hCodfFOGMDW1jY9qhs3d3ehGEC/d7KeQ79KBex2W0I/gPJQtLNHTzkNtINfNv+3r gaES/lz/jpzhWXMmNya0mRQafoXaUtVvwHieVZxlX75VIHCmZdA1jpZtaaseJF8qctG0 E7xMGcJPR2B8IvHxxGLyJgUPRxtBjqUxULc+ReTox529Sl5GpDjmv7bvsBotS9X4OvKN nv1XChDadMRN2uhJl4ZsQ0danW3BZtabA9Gm04MF2bqw9OsRbUo+1BsIg/VlA99h2jd7 zwBAaCVS+pQWgxaG+rnv2DWZNho+CkDdmxEN5bjj5N404SvmyFbTzsoyXEfjVnl4eASr oPXg== 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; bh=KBk3bK4feaNc3+lvwrD6wznDNxRkOBFpu408+U2igpg=; b=AF7ofsUGFEZpeCZ5DUht1YFr3wSZKc2RjY+Km0fKj2eheTkdNUSUkuFPY09o0hEFsA hBz22iwmJhOMiJDAoXOy8ifhplqwwAZr5S/UG7G0WD82dGaK9p3aUTtcU1FMcJJTKhWe p5V9G++TsUgWFb40dCDLKD05+FjJY40gi2kLSdPp22s2jC38loNOBehlHHuMP819HTrE gvx98jIffOXJ6Hc+daR54RZkpAdXzJfkMMoQJ7+SkbDnUbX8zv77vf8P8JfpgJsRVC9T yvOGp9Tp18AXpyBqEfjyDMy6SKssTAUIwJNhfCltgGK73kcofTDEimDgDDVrvFIRXntA iiow== X-Gm-Message-State: AOAM532+h0KYCGAhFbvdFYaJ20ZzSZleuHiespLUvoU7YoMsGc4x8T3E iveVQZFUsOTeAbv54Yk7Vz4= X-Google-Smtp-Source: ABdhPJxtMG1mATh/nmL1MzTEC2niGJF4DF7sAoEKS2wZPWSiGh81t64IO1exrtSh3BCtML8wMI14Yg== X-Received: by 2002:a65:590a:: with SMTP id f10mr1887791pgu.358.1618630364012; Fri, 16 Apr 2021 20:32:44 -0700 (PDT) Received: from ast-mbp.thefacebook.com ([163.114.132.7]) by smtp.gmail.com with ESMTPSA id h1sm6069870pgv.88.2021.04.16.20.32.42 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Apr 2021 20:32:43 -0700 (PDT) From: Alexei Starovoitov To: davem@davemloft.net Cc: daniel@iogearbox.net, andrii@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH bpf-next 12/15] libbpf: Change the order of data and text relocations. Date: Fri, 16 Apr 2021 20:32:21 -0700 Message-Id: <20210417033224.8063-13-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.13.5 In-Reply-To: <20210417033224.8063-1-alexei.starovoitov@gmail.com> References: <20210417033224.8063-1-alexei.starovoitov@gmail.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Alexei Starovoitov In order to be able to generate loader program in the later patches change the order of data and text relocations. Also improve the test to include data relos. Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/libbpf.c | 82 ++++++++++++++----- .../selftests/bpf/progs/test_subprogs.c | 13 +++ 2 files changed, 76 insertions(+), 19 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 17cfc5b66111..083e441d9c5e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6379,11 +6379,15 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) insn[0].imm = ext->ksym.kernel_btf_id; break; case RELO_SUBPROG_ADDR: - insn[0].src_reg = BPF_PSEUDO_FUNC; - /* will be handled as a follow up pass */ + if (insn[0].src_reg != BPF_PSEUDO_FUNC) { + pr_warn("prog '%s': relo #%d: bad insn\n", + prog->name, i); + return -EINVAL; + } + /* handled already */ break; case RELO_CALL: - /* will be handled as a follow up pass */ + /* handled already */ break; default: pr_warn("prog '%s': relo #%d: bad relo type %d\n", @@ -6552,6 +6556,31 @@ static struct reloc_desc *find_prog_insn_relo(const struct bpf_program *prog, si sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx); } +static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_program *subprog) +{ + int new_cnt = main_prog->nr_reloc + subprog->nr_reloc; + struct reloc_desc *relos; + size_t off = subprog->sub_insn_off; + int i; + + if (main_prog == subprog) + return 0; + relos = libbpf_reallocarray(main_prog->reloc_desc, new_cnt, sizeof(*relos)); + if (!relos) + return -ENOMEM; + memcpy(relos + main_prog->nr_reloc, subprog->reloc_desc, + sizeof(*relos) * subprog->nr_reloc); + + for (i = main_prog->nr_reloc; i < new_cnt; i++) + relos[i].insn_idx += off; + /* After insn_idx adjustment the 'relos' array is still sorted + * by insn_idx and doesn't break bsearch. + */ + main_prog->reloc_desc = relos; + main_prog->nr_reloc = new_cnt; + return 0; +} + static int bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, struct bpf_program *prog) @@ -6560,12 +6589,21 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, struct bpf_program *subprog; struct bpf_insn *insns, *insn; struct reloc_desc *relo; - int err; + int err, i; err = reloc_prog_func_and_line_info(obj, main_prog, prog); if (err) return err; + for (i = 0; i < prog->nr_reloc; i++) { + relo = &prog->reloc_desc[i]; + insn = &main_prog->insns[prog->sub_insn_off + relo->insn_idx]; + + if (relo->type == RELO_SUBPROG_ADDR) + /* mark the insn, so it becomes insn_is_pseudo_func() */ + insn[0].src_reg = BPF_PSEUDO_FUNC; + } + for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) { insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; if (!insn_is_subprog_call(insn) && !insn_is_pseudo_func(insn)) @@ -6573,6 +6611,8 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, relo = find_prog_insn_relo(prog, insn_idx); if (relo && relo->type != RELO_CALL && relo->type != RELO_SUBPROG_ADDR) { + if (relo->type == RELO_EXTERN_FUNC) + continue; pr_warn("prog '%s': unexpected relo for insn #%zu, type %d\n", prog->name, insn_idx, relo->type); return -LIBBPF_ERRNO__RELOC; @@ -6646,6 +6686,10 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n", main_prog->name, subprog->insns_cnt, subprog->name); + /* The subprog insns are now appended. Append its relos too. */ + err = append_subprog_relos(main_prog, subprog); + if (err) + return err; err = bpf_object__reloc_code(obj, main_prog, subprog); if (err) return err; @@ -6790,23 +6834,11 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) return err; } } - /* relocate data references first for all programs and sub-programs, - * as they don't change relative to code locations, so subsequent - * subprogram processing won't need to re-calculate any of them - */ - for (i = 0; i < obj->nr_programs; i++) { - prog = &obj->programs[i]; - err = bpf_object__relocate_data(obj, prog); - if (err) { - pr_warn("prog '%s': failed to relocate data references: %d\n", - prog->name, err); - return err; - } - } - /* now relocate subprogram calls and append used subprograms to main + /* relocate subprogram calls and append used subprograms to main * programs; each copy of subprogram code needs to be relocated * differently for each main program, because its code location might - * have changed + * have changed. + * Append subprog relos to main programs. */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; @@ -6823,6 +6855,18 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) return err; } } + /* Process data relos for main programs */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + if (prog_is_subprog(obj, prog)) + continue; + err = bpf_object__relocate_data(obj, prog); + if (err) { + pr_warn("prog '%s': failed to relocate data references: %d\n", + prog->name, err); + return err; + } + } /* free up relocation descriptors */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; diff --git a/tools/testing/selftests/bpf/progs/test_subprogs.c b/tools/testing/selftests/bpf/progs/test_subprogs.c index d3c5673c0218..b7c37ca09544 100644 --- a/tools/testing/selftests/bpf/progs/test_subprogs.c +++ b/tools/testing/selftests/bpf/progs/test_subprogs.c @@ -4,8 +4,18 @@ const char LICENSE[] SEC("license") = "GPL"; +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u64); +} array SEC(".maps"); + __noinline int sub1(int x) { + int key = 0; + + bpf_map_lookup_elem(&array, &key); return x + 1; } @@ -23,6 +33,9 @@ static __noinline int sub3(int z) static __noinline int sub4(int w) { + int key = 0; + + bpf_map_lookup_elem(&array, &key); return w + sub3(5) + sub1(6); }