From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28D0DC433EF for ; Tue, 12 Jul 2022 18:45:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234338AbiGLSpb (ORCPT ); Tue, 12 Jul 2022 14:45:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234268AbiGLSo7 (ORCPT ); Tue, 12 Jul 2022 14:44:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5985CDABAB; Tue, 12 Jul 2022 11:42:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BA2DF61AD2; Tue, 12 Jul 2022 18:42:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBBEBC341D0; Tue, 12 Jul 2022 18:42:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657651343; bh=KOPBfmIxu9SkTNKcXX0nwvznMmnj5WtPQ0BxdN1yLmw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PptCVk9+l2dstg2j5TXkXLJNJdDCEmTnQgKZNG20h0EivWtcoCNw9sOmiJhLihfUr 4gAiB4RDsMflkkRDKoAm+V7tOgIs/k2QJ5qSWKXa5ERAkhokdUTi7SFMezsP2vencn ZmsDpeg9OzSNKkRspCO8/gUqK9KnT0tY3m9K3wug= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Poimboeuf , Ben Hutchings Subject: [PATCH 5.10 007/130] objtool: Assume only ELF functions do sibling calls Date: Tue, 12 Jul 2022 20:37:33 +0200 Message-Id: <20220712183246.727242541@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220712183246.394947160@linuxfoundation.org> References: <20220712183246.394947160@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josh Poimboeuf commit ecf11ba4d066fe527586c6edd6ca68457ca55cf4 upstream. There's an inconsistency in how sibling calls are detected in non-function asm code, depending on the scope of the object. If the target code is external to the object, objtool considers it a sibling call. If the target code is internal but not a function, objtool *doesn't* consider it a sibling call. This can cause some inconsistencies between per-object and vmlinux.o validation. Instead, assume only ELF functions can do sibling calls. This generally matches existing reality, and makes sibling call validation consistent between vmlinux.o and per-object. Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/0e9ab6f3628cc7bf3bde7aa6762d54d7df19ad78.1611263461.git.jpoimboe@redhat.com Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- tools/objtool/check.c | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -109,15 +109,20 @@ static struct instruction *prev_insn_sam static bool is_sibling_call(struct instruction *insn) { + /* + * Assume only ELF functions can make sibling calls. This ensures + * sibling call detection consistency between vmlinux.o and individual + * objects. + */ + if (!insn->func) + return false; + /* An indirect jump is either a sibling call or a jump to a table. */ if (insn->type == INSN_JUMP_DYNAMIC) return list_empty(&insn->alts); - if (!is_static_jump(insn)) - return false; - /* add_jump_destinations() sets insn->call_dest for sibling calls. */ - return !!insn->call_dest; + return (is_static_jump(insn) && insn->call_dest); } /* @@ -788,7 +793,7 @@ static int add_jump_destinations(struct continue; reloc = find_reloc_by_dest_range(file->elf, insn->sec, - insn->offset, insn->len); + insn->offset, insn->len); if (!reloc) { dest_sec = insn->sec; dest_off = arch_jump_destination(insn); @@ -808,18 +813,21 @@ static int add_jump_destinations(struct insn->retpoline_safe = true; continue; - } else if (reloc->sym->sec->idx) { - dest_sec = reloc->sym->sec; - dest_off = reloc->sym->sym.st_value + - arch_dest_reloc_offset(reloc->addend); - } else { - /* external sibling call */ + } else if (insn->func) { + /* internal or external sibling call (with reloc) */ insn->call_dest = reloc->sym; if (insn->call_dest->static_call_tramp) { list_add_tail(&insn->static_call_node, &file->static_call_list); } continue; + } else if (reloc->sym->sec->idx) { + dest_sec = reloc->sym->sec; + dest_off = reloc->sym->sym.st_value + + arch_dest_reloc_offset(reloc->addend); + } else { + /* non-func asm code jumping to another file */ + continue; } insn->jump_dest = find_insn(file, dest_sec, dest_off); @@ -868,7 +876,7 @@ static int add_jump_destinations(struct } else if (insn->jump_dest->func->pfunc != insn->func->pfunc && insn->jump_dest->offset == insn->jump_dest->func->offset) { - /* internal sibling call */ + /* internal sibling call (without reloc) */ insn->call_dest = insn->jump_dest->func; if (insn->call_dest->static_call_tramp) { list_add_tail(&insn->static_call_node, @@ -2570,7 +2578,7 @@ static int validate_branch(struct objtoo case INSN_JUMP_CONDITIONAL: case INSN_JUMP_UNCONDITIONAL: - if (func && is_sibling_call(insn)) { + if (is_sibling_call(insn)) { ret = validate_sibling_call(insn, &state); if (ret) return ret; @@ -2592,7 +2600,7 @@ static int validate_branch(struct objtoo case INSN_JUMP_DYNAMIC: case INSN_JUMP_DYNAMIC_CONDITIONAL: - if (func && is_sibling_call(insn)) { + if (is_sibling_call(insn)) { ret = validate_sibling_call(insn, &state); if (ret) return ret;