From patchwork Thu Jun 25 20:02:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 11626069 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 9CEC5138C for ; Thu, 25 Jun 2020 20:03:07 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 5879F20789 for ; Thu, 25 Jun 2020 20:03:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="DyyM5Sav" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5879F20789 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19171-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 32472 invoked by uid 550); 25 Jun 2020 20:03:04 -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 32452 invoked from network); 25 Jun 2020 20:03:04 -0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=FsDT+UwWj8NjanG08/h+QS1cpoNn0JdTXUHH0/+8kpM=; b=DyyM5Sav88XHl/TmWuCfgQ1Vh+ SdivkS07u1y74bQS+jecF+JTmw/LKf2EuJa8tPQaJyQFAjVRvyfVMRi5LNy1T96kic0n0iCNjdIC+ k0bqeJB2ZhvOAHzPXbW+0SPwMuwdEpA/sGG3zDU2TCqYnkDXYP1VEMxNe+0hp/sA6Uu5sDSZWoFoe CFJL+fD7MsR6RUh+BlD6O7SEPdqWXyis2H1uPUXRQnIw7XrQk3m5z8Sp6TWiWYsyqdOr05FjAwILf siJpQN/KKgSpTv+sZne5M3hvxcPanw9qNN9pitpRmbq5G8MjetRvJOAO6m6eCldOUT1S3MJv511Wg OF33jN1A==; Date: Thu, 25 Jun 2020 22:02:35 +0200 From: Peter Zijlstra To: Sami Tolvanen Cc: Steven Rostedt , Masahiro Yamada , Will Deacon , 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, Josh Poimboeuf , mhelsley@vmware.com Subject: [RFC][PATCH] objtool,x86_64: Replace recordmcount with objtool Message-ID: <20200625200235.GQ4781@hirez.programming.kicks-ass.net> References: <20200624203200.78870-1-samitolvanen@google.com> <20200624203200.78870-5-samitolvanen@google.com> <20200624212737.GV4817@hirez.programming.kicks-ass.net> <20200624214530.GA120457@google.com> <20200625074530.GW4817@hirez.programming.kicks-ass.net> <20200625161503.GB173089@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200625161503.GB173089@google.com> On Thu, Jun 25, 2020 at 09:15:03AM -0700, Sami Tolvanen wrote: > On Thu, Jun 25, 2020 at 09:45:30AM +0200, Peter Zijlstra wrote: > > At least for x86_64 I can do a really quick take for a recordmcount pass > > in objtool, but I suppose you also need this for ARM64 ? > > Sure, sounds good. arm64 uses -fpatchable-function-entry with clang, so we > don't need recordmcount there. This is on top of my local pile: git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git master which notably includes the static_call series. Not boot tested, but it generates the required sections and they look more or less as expected, ymmv. --- arch/x86/Kconfig | 1 - scripts/Makefile.build | 3 ++ scripts/link-vmlinux.sh | 2 +- tools/objtool/builtin-check.c | 9 ++--- tools/objtool/builtin.h | 2 +- tools/objtool/check.c | 81 +++++++++++++++++++++++++++++++++++++++++++ tools/objtool/check.h | 1 + tools/objtool/objtool.h | 1 + 8 files changed, 91 insertions(+), 9 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index a291823f3f26..189575c12434 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -174,7 +174,6 @@ config X86 select HAVE_EXIT_THREAD select HAVE_FAST_GUP select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE - select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER select HAVE_GCC_PLUGINS diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 2e8810b7e5ed..c774befc57da 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -227,6 +227,9 @@ endif ifdef CONFIG_X86_SMAP objtool_args += --uaccess endif +ifdef CONFIG_DYNAMIC_FTRACE + objtool_args += --mcount +endif # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 92dd745906f4..00c6e4f28a1a 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -60,7 +60,7 @@ objtool_link() local objtoolopt; if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then - objtoolopt="check" + objtoolopt="check --vmlinux" if [ -z "${CONFIG_FRAME_POINTER}" ]; then objtoolopt="${objtoolopt} --no-fp" fi diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 4896c5a89702..a6c3a3fba67d 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, fpu; +bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu, mcount; static const char * const check_usage[] = { "objtool check [] file.o", @@ -36,12 +36,13 @@ const struct option check_options[] = { OPT_BOOLEAN('d', "duplicate", &validate_dup, "duplicate validation for vmlinux.o"), OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"), OPT_BOOLEAN('F', "fpu", &fpu, "validate FPU context"), + OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"), OPT_END(), }; int cmd_check(int argc, const char **argv) { - const char *objname, *s; + const char *objname; argc = parse_options(argc, argv, check_options, check_usage, 0); @@ -50,9 +51,5 @@ int cmd_check(int argc, const char **argv) objname = argv[0]; - s = strstr(objname, "vmlinux.o"); - if (s && !s[9]) - vmlinux = true; - return check(objname, false); } diff --git a/tools/objtool/builtin.h b/tools/objtool/builtin.h index 7158e09d4cc9..b51d883ec245 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, fpu; +extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu, 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 6647a8d1545b..ee99566bdae9 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -533,6 +533,65 @@ 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. */ @@ -892,6 +951,22 @@ 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. @@ -3004,6 +3079,7 @@ int check(const char *_objname, bool orc) 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; @@ -3056,6 +3132,11 @@ int check(const char *_objname, bool orc) goto out; warnings += ret; + 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 cd95fca0d237..01f11b5da5dd 100644 --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -24,6 +24,7 @@ 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.h b/tools/objtool/objtool.h index 9a7cd0b88bd8..f604b22d22cc 100644 --- a/tools/objtool/objtool.h +++ b/tools/objtool/objtool.h @@ -17,6 +17,7 @@ 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; };