From patchwork Tue Oct 13 00:31:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11834549 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 D26D714D5 for ; Tue, 13 Oct 2020 00:32:36 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 0419521BE5 for ; Tue, 13 Oct 2020 00:32:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="IXTPLb0y" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0419521BE5 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-20175-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 11322 invoked by uid 550); 13 Oct 2020 00:32:22 -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 10185 invoked from network); 13 Oct 2020 00:32:22 -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=TMDqK7SaU5cOFiGBMdZ8Uvp/vuFhiQD2dpfcaMKefDQ=; b=IXTPLb0yFS0o2Ga79gr7xdNEuO4HV13KRVxV2TTekWKuTZxx//v6pgCz5d15EYldkD BZ57RN/e61FhDemXvwUx/f/NWB6TRPm+Js/jxH+Ozhr38+xqoMr+mLGrfiRquS2j3kZJ fYrUrVndpVuef4YOld3pXFi3jcBOAwRlkcsfQZwg/xUdayEHuKtVYacnXMtm0b/I38Qx WxiKUnZ+mL2wNK3BuVJubCd8sZKHY38WZpOm/vNkaFMYl+vqbCp10u/22PEAKbjAh45D sMdah9r1FW+zKiF03OY7alXL/9E4fBd9YI1yEFlLk7unOBGLusyORO3j8boBtmXDyJax UZbw== 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=TMDqK7SaU5cOFiGBMdZ8Uvp/vuFhiQD2dpfcaMKefDQ=; b=ZsDQIF6Bzo8sR/2JlaP3+XqfmVg8cst07C7JvgBRFsfGqNzbdLwCqcn+nKbzgDyX0k VTxtgojAlasNRbAWf9emPO4hhm0b5ddX+v4n1kt8jZzh9JIg4+Ed9rhp7MZ7ED+fImfA YIaoMkeLtQbcBRGHXEklvswZhQmDI4F7YNUHdWapoIVPIKxvzm1/0pulChMrVXLg8yrL 7dUNrZ03l3XHLCY/59iSBqNkC/ok4lFJ7x+jF7HnPS8I9+MQJG/MJ0QHz1wjNT4JUB83 0FYgunjNFD68CiiJldxVHJnjXgZfYie9IePCUFf/QPfdTD7jPcG88uaWIFBthZTij3i7 1qOw== X-Gm-Message-State: AOAM532lN5lKZj4/HutBjHXoD6PA3cRiJiTWf1HVx/15oP7M289HPB75 ltkDOmkkViWGyo/azrNeTSgpkndeGvTpwZHmHiI= X-Google-Smtp-Source: ABdhPJzsd4CCmnhcLZkBRbfSKkJeEB8ZYCNEDRSF1U6z3faMrYXBKcMOZdLok8oHysnniolDxRFIZGt/9cwSiZFRwQU= 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:a17:90a:940c:: with SMTP id r12mr3210626pjo.1.1602549129256; Mon, 12 Oct 2020 17:32:09 -0700 (PDT) Date: Mon, 12 Oct 2020 17:31:40 -0700 In-Reply-To: <20201013003203.4168817-1-samitolvanen@google.com> Message-Id: <20201013003203.4168817-3-samitolvanen@google.com> Mime-Version: 1.0 References: <20201013003203.4168817-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH v6 02/25] objtool: Add a pass for generating __mcount_loc From: Sami Tolvanen To: Masahiro Yamada , Steven Rostedt Cc: Will Deacon , Peter Zijlstra , 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, 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 | 82 +++++++++++++++++++++++++++++++++++ tools/objtool/check.h | 1 + tools/objtool/objtool.c | 1 + tools/objtool/objtool.h | 1 + 6 files changed, 88 insertions(+), 2 deletions(-) diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index c6d199bfd0ae..e92e76f69176 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 c6ab44543c92..c39c4d2b432a 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -523,6 +523,65 @@ static int create_static_call_sections(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", 0, 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. */ @@ -949,6 +1008,22 @@ 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. @@ -2920,6 +2995,13 @@ int check(struct objtool_file *file) goto out; warnings += ret; + if (mcount) { + ret = create_mcount_loc_sections(file); + if (ret < 0) + goto out; + warnings += ret; + } + out: if (ret < 0) { /* diff --git a/tools/objtool/check.h b/tools/objtool/check.h index 5ec00a4b891b..070baec2050a 100644 --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -23,6 +23,7 @@ struct instruction { struct list_head list; struct hlist_node hash; struct list_head static_call_node; + struct list_head mcount_loc_node; struct section *sec; unsigned long offset; unsigned int len; diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c index 9df0cd86d310..c1819a6f2a18 100644 --- a/tools/objtool/objtool.c +++ b/tools/objtool/objtool.c @@ -62,6 +62,7 @@ struct objtool_file *objtool_open_read(const char *_objname) INIT_LIST_HEAD(&file.insn_list); hash_init(file.insn_hash); INIT_LIST_HEAD(&file.static_call_list); + 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; diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h index 4125d4578b23..cf004dd60c2b 100644 --- a/tools/objtool/objtool.h +++ b/tools/objtool/objtool.h @@ -19,6 +19,7 @@ struct objtool_file { struct list_head insn_list; DECLARE_HASHTABLE(insn_hash, 20); struct list_head static_call_list; + struct list_head mcount_loc_list; bool ignore_unreachables, c_file, hints, rodata; };