From patchwork Thu Sep 3 20:30:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11754731 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 16FD2746 for ; Thu, 3 Sep 2020 20:31:52 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 4475620C56 for ; Thu, 3 Sep 2020 20:31:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="VveOi2tH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4475620C56 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19724-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 18341 invoked by uid 550); 3 Sep 2020 20:31:18 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 18192 invoked from network); 3 Sep 2020 20:31:17 -0000 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=Ygth48f6RQ7AVK3M037lXI5lSip58PlMRJWKWtM7ReM=; b=VveOi2tHUhJYrFJ6jIZsoPFYgSPEG1VrYrwXyKUSNgOeF4zvromJm+bPaJc9r6p17B xvhOw7cFDtl6haPVhs2xQbizEhLtrnAsP+m1iS8aSNBrHHBONC5VbqvRXrDtSwFsWSf7 zEbw+oEOcqIWYYB57zTqb8o2KyvJTD/deul/7DsBBtPjQUSJyvZtTrcxWWmtmA/0T6eT Ry3BjPrZIeJ1PUyqRECawCQwtDW4WqGIqsZbCjb93HOQusaouqohbd87BofC5UiMHBQi +TRCT/C0DNSWYTBUrZBANISvKjFYcn/luvJizgqSba0Z1TWUXVpaPMtdTLBXtSuEKZwc kJ0g== 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=Ygth48f6RQ7AVK3M037lXI5lSip58PlMRJWKWtM7ReM=; b=ZGeLSeE3efAGs1+DNKDK1jEO+8LSA5KJtVXEkWqGlxMJ6jgowN1AOo3Q0lrvwOMjyL KNEFqxJC9PrZVXg/NeDvvCUh7n6JpUcSL3EkD2+TQhmPde38eEmNgOlSU+bRUNuoCJ6Q ePCmfvh3YeCSeB5bcCVoL8jx6S8KJe1VbgosknbjjoDcxKupNlpyAD+7YGJklktQaY6H RkvZsOuND+TD1aL5XDY4TzkQ/X+7LTql/LxBWI/Z7Hjdgqi39dIJAlD9mMnWvhTPQPat kmb0SnCNEt9gFcp6cS45o9PBvxpB1u9wk1GPYwK1uhkAgeUa8Cp8Inmd4+7cR9b4v2jt b9vA== X-Gm-Message-State: AOAM533wqn1B62itUi6VO+waeRKkjQ5DSRQv97G1wgpknoQCuZMn2C1G CJ9iNpAtQBoUnrvzgibmSzccPS03y0jxvKdcG+4= X-Google-Smtp-Source: ABdhPJz85W6DE6Mm6fnLwMg8VMiWlldCr2fUmeCkDf6x0DGkEohQdcvqsi3V1rklGdldQ2YiHbOOTbnEtQo0Frap2UI= Sender: "samitolvanen via sendgmr" X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:a62:1cc4:0:b029:13c:1611:653d with SMTP id c187-20020a621cc40000b029013c1611653dmr3883611pfc.15.1599165065144; Thu, 03 Sep 2020 13:31:05 -0700 (PDT) Date: Thu, 3 Sep 2020 13:30:30 -0700 In-Reply-To: <20200903203053.3411268-1-samitolvanen@google.com> Message-Id: <20200903203053.3411268-6-samitolvanen@google.com> Mime-Version: 1.0 References: <20200624203200.78870-1-samitolvanen@google.com> <20200903203053.3411268-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.526.ge36021eeef-goog Subject: [PATCH v2 05/28] objtool: Add a pass for generating __mcount_loc From: Sami Tolvanen To: Masahiro Yamada , Will Deacon Cc: Peter Zijlstra , Steven Rostedt , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org, Sami Tolvanen From: Peter Zijlstra Add the --mcount option for generating __mcount_loc sections needed for dynamic ftrace. Using this pass requires the kernel to be compiled with -mfentry and CC_USING_NOP_MCOUNT to be defined in Makefile. Link: https://lore.kernel.org/lkml/20200625200235.GQ4781@hirez.programming.kicks-ass.net/ Signed-off-by: Peter Zijlstra [Sami: rebased to mainline, dropped config changes, fixed to actually use --mcount, and wrote a commit message.] Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- tools/objtool/builtin-check.c | 3 +- tools/objtool/builtin.h | 2 +- tools/objtool/check.c | 83 +++++++++++++++++++++++++++++++++++ tools/objtool/check.h | 1 + tools/objtool/objtool.h | 1 + 5 files changed, 88 insertions(+), 2 deletions(-) diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 7a44174967b5..71595cf4946d 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -18,7 +18,7 @@ #include "builtin.h" #include "objtool.h" -bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux; +bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount; static const char * const check_usage[] = { "objtool check [] file.o", @@ -35,6 +35,7 @@ const struct option check_options[] = { OPT_BOOLEAN('s', "stats", &stats, "print statistics"), OPT_BOOLEAN('d', "duplicate", &validate_dup, "duplicate validation for vmlinux.o"), OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"), + OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"), OPT_END(), }; diff --git a/tools/objtool/builtin.h b/tools/objtool/builtin.h index 85c979caa367..94565a72b701 100644 --- a/tools/objtool/builtin.h +++ b/tools/objtool/builtin.h @@ -8,7 +8,7 @@ #include extern const struct option check_options[]; -extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux; +extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount; extern int cmd_check(int argc, const char **argv); extern int cmd_orc(int argc, const char **argv); diff --git a/tools/objtool/check.c b/tools/objtool/check.c index e034a8f24f46..6e0b478dc065 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -433,6 +433,65 @@ static int add_dead_ends(struct objtool_file *file) return 0; } +static int create_mcount_loc_sections(struct objtool_file *file) +{ + struct section *sec, *reloc_sec; + struct reloc *reloc; + unsigned long *loc; + struct instruction *insn; + int idx; + + sec = find_section_by_name(file->elf, "__mcount_loc"); + if (sec) { + INIT_LIST_HEAD(&file->mcount_loc_list); + WARN("file already has __mcount_loc section, skipping"); + return 0; + } + + if (list_empty(&file->mcount_loc_list)) + return 0; + + idx = 0; + list_for_each_entry(insn, &file->mcount_loc_list, mcount_loc_node) + idx++; + + sec = elf_create_section(file->elf, "__mcount_loc", sizeof(unsigned long), idx); + if (!sec) + return -1; + + reloc_sec = elf_create_reloc_section(file->elf, sec, SHT_RELA); + if (!reloc_sec) + return -1; + + idx = 0; + list_for_each_entry(insn, &file->mcount_loc_list, mcount_loc_node) { + + loc = (unsigned long *)sec->data->d_buf + idx; + memset(loc, 0, sizeof(unsigned long)); + + reloc = malloc(sizeof(*reloc)); + if (!reloc) { + perror("malloc"); + return -1; + } + memset(reloc, 0, sizeof(*reloc)); + + reloc->sym = insn->sec->sym; + reloc->addend = insn->offset; + reloc->type = R_X86_64_64; + reloc->offset = idx * sizeof(unsigned long); + reloc->sec = reloc_sec; + elf_add_reloc(file->elf, reloc); + + idx++; + } + + if (elf_rebuild_reloc_section(file->elf, reloc_sec)) + return -1; + + return 0; +} + /* * Warnings shouldn't be reported for ignored functions. */ @@ -784,6 +843,22 @@ static int add_call_destinations(struct objtool_file *file) insn->type = INSN_NOP; } + if (mcount && !strcmp(insn->call_dest->name, "__fentry__")) { + if (reloc) { + reloc->type = R_NONE; + elf_write_reloc(file->elf, reloc); + } + + elf_write_insn(file->elf, insn->sec, + insn->offset, insn->len, + arch_nop_insn(insn->len)); + + insn->type = INSN_NOP; + + list_add_tail(&insn->mcount_loc_node, + &file->mcount_loc_list); + } + /* * Whatever stack impact regular CALLs have, should be undone * by the RETURN of the called function. @@ -2791,6 +2866,7 @@ int check(const char *_objname, bool orc) INIT_LIST_HEAD(&file.insn_list); hash_init(file.insn_hash); + INIT_LIST_HEAD(&file.mcount_loc_list); file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment"); file.ignore_unreachables = no_unreachable; file.hints = false; @@ -2838,6 +2914,13 @@ int check(const char *_objname, bool orc) warnings += ret; } + if (mcount) { + ret = create_mcount_loc_sections(&file); + if (ret < 0) + goto out; + warnings += ret; + } + if (orc) { ret = create_orc(&file); if (ret < 0) diff --git a/tools/objtool/check.h b/tools/objtool/check.h index 061aa96e15d3..b62afd3d970b 100644 --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -22,6 +22,7 @@ struct insn_state { struct instruction { struct list_head list; struct hlist_node hash; + struct list_head mcount_loc_node; struct section *sec; unsigned long offset; unsigned int len; diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h index 528028a66816..427806079540 100644 --- a/tools/objtool/objtool.h +++ b/tools/objtool/objtool.h @@ -16,6 +16,7 @@ struct objtool_file { struct elf *elf; struct list_head insn_list; DECLARE_HASHTABLE(insn_hash, 20); + struct list_head mcount_loc_list; bool ignore_unreachables, c_file, hints, rodata; };