Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934946AbeAONBP (ORCPT + 1 other); Mon, 15 Jan 2018 08:01:15 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:51696 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967246AbeAOMvf (ORCPT ); Mon, 15 Jan 2018 07:51:35 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Poimboeuf , David Woodhouse , Thomas Gleixner , gnomes@lxorguk.ukuu.org.uk, Rik van Riel , Andi Kleen , thomas.lendacky@amd.com, Peter Zijlstra , Linus Torvalds , Jiri Kosina , Andy Lutomirski , Dave Hansen , Kees Cook , Tim Chen , Paul Turner , Greg Kroah-Hartman Subject: [PATCH 4.14 102/118] objtool: Detect jumps to retpoline thunks Date: Mon, 15 Jan 2018 13:35:29 +0100 Message-Id: <20180115123421.463467857@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180115123415.325497625@linuxfoundation.org> References: <20180115123415.325497625@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josh Poimboeuf commit 39b735332cb8b33a27c28592d969e4016c86c3ea upstream. A direct jump to a retpoline thunk is really an indirect jump in disguise. Change the objtool instruction type accordingly. Objtool needs to know where indirect branches are so it can detect switch statement jump tables. This fixes a bunch of warnings with CONFIG_RETPOLINE like: arch/x86/events/intel/uncore_nhmex.o: warning: objtool: nhmex_rbox_msr_enable_event()+0x44: sibling call from callable instruction with modified stack frame kernel/signal.o: warning: objtool: copy_siginfo_to_user()+0x91: sibling call from callable instruction with modified stack frame ... Signed-off-by: Josh Poimboeuf Signed-off-by: David Woodhouse Signed-off-by: Thomas Gleixner Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel Cc: Andi Kleen Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Jiri Kosina Cc: Andy Lutomirski Cc: Dave Hansen Cc: Kees Cook Cc: Tim Chen Cc: Greg Kroah-Hartman Cc: Paul Turner Link: https://lkml.kernel.org/r/1515707194-20531-2-git-send-email-dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman --- tools/objtool/check.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -456,6 +456,13 @@ static int add_jump_destinations(struct } else if (rela->sym->sec->idx) { dest_sec = rela->sym->sec; dest_off = rela->sym->sym.st_value + rela->addend + 4; + } else if (strstr(rela->sym->name, "_indirect_thunk_")) { + /* + * Retpoline jumps are really dynamic jumps in + * disguise, so convert them accordingly. + */ + insn->type = INSN_JUMP_DYNAMIC; + continue; } else { /* sibling call */ insn->jump_dest = 0;