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 X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39DE2C43331 for ; Thu, 2 Apr 2020 08:18:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0BFD4208E0 for ; Thu, 2 Apr 2020 08:18:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="VM0hpYBh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387820AbgDBISq (ORCPT ); Thu, 2 Apr 2020 04:18:46 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:35644 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387801AbgDBISo (ORCPT ); Thu, 2 Apr 2020 04:18:44 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0328HYgu077899; Thu, 2 Apr 2020 08:18:22 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=G2EUQCFwJX8XuZno6OD5sAaFtbX5f0F6eswOa4/kh0g=; b=VM0hpYBhPhk6BAiUwVAv9RIvkCXW7iuI5T9EBdGrgrDnPgjhoCE0uHef3+vo76qami/+ wTGFU4UKLHzrVVQJektnQEcEF3wqIoSoOUnGK8HHS5XHXEEZGUGA0Dh86PifuPhSeZjY tRJaq1hxYDJI0RcCYmK17XNxIUXLXgGVsfDh8GegCn+ZVNflgzEZw2lMDw0AztBBPGbF tKjv8yYmcgMiZFPmn4EdRybJEz3aDGFtqnkomHdRorYxfKW2VymU+pQi72V8UH6rC5jo 5Gxc9TFpC4i7BI4W8hvGBOK0sD7LDnYi61vPVZpFHhphjCv7AGRY6Ue2BLld7/v0a2Ek SQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 303cev9u7t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 02 Apr 2020 08:18:22 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0328IJeH090968; Thu, 2 Apr 2020 08:18:21 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 302g4v4phu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 02 Apr 2020 08:18:20 +0000 Received: from abhmp0011.oracle.com (abhmp0011.oracle.com [141.146.116.17]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0328IFaS003424; Thu, 2 Apr 2020 08:18:15 GMT Received: from linux-1.home (/92.157.90.160) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 02 Apr 2020 01:18:15 -0700 From: Alexandre Chartre To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, jpoimboe@redhat.com, peterz@infradead.org, jthierry@redhat.com, tglx@linutronix.de, alexandre.chartre@oracle.com Subject: [PATCH 3/7] objtool: Add support for intra-function calls Date: Thu, 2 Apr 2020 10:22:16 +0200 Message-Id: <20200402082220.808-4-alexandre.chartre@oracle.com> X-Mailer: git-send-email 2.18.2 In-Reply-To: <20200402082220.808-1-alexandre.chartre@oracle.com> References: <20200402082220.808-1-alexandre.chartre@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9578 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 bulkscore=0 suspectscore=1 mlxscore=0 spamscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004020075 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9578 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 adultscore=0 clxscore=1015 phishscore=0 lowpriorityscore=0 spamscore=0 malwarescore=0 suspectscore=1 mlxscore=0 impostorscore=0 mlxlogscore=999 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004020075 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Change objtool to support intra-function calls. An intra-function call is represented in objtool as a push onto the stack (of the return address), and a jump to the destination address. That way the stack information is correctly updated and the call flow is still accurate. Signed-off-by: Alexandre Chartre --- tools/objtool/check.c | 73 ++++++++++++++++++++++++++++++++++++++++++- tools/objtool/check.h | 1 + 2 files changed, 73 insertions(+), 1 deletion(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 214809ac2776..0cec91291d46 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -657,6 +657,18 @@ static int add_call_destinations(struct objtool_file *file) if (insn->type != INSN_CALL) continue; + if (insn->intra_function_call) { + dest_off = insn->offset + insn->len + insn->immediate; + insn->jump_dest = find_insn(file, insn->sec, dest_off); + if (insn->jump_dest) + continue; + + WARN_FUNC("can't find call dest at %s+0x%lx", + insn->sec, insn->offset, + insn->sec->name, dest_off); + return -1; + } + rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len); if (!rela) { @@ -1289,6 +1301,49 @@ static int read_retpoline_hints(struct objtool_file *file) return 0; } +static int read_intra_function_call(struct objtool_file *file) +{ + struct section *sec; + struct instruction *insn; + struct rela *rela; + + sec = find_section_by_name(file->elf, + ".rela.discard.intra_function_call"); + if (!sec) + return 0; + + list_for_each_entry(rela, &sec->rela_list, list) { + if (rela->sym->type != STT_SECTION) { + WARN("unexpected relocation symbol type in %s", + sec->name); + return -1; + } + + insn = find_insn(file, rela->sym->sec, rela->addend); + if (!insn) { + WARN("bad .discard.intra_function_call entry"); + return -1; + } + + if (insn->type != INSN_CALL) { + WARN_FUNC("intra_function_call not a call", + insn->sec, insn->offset); + return -1; + } + + insn->intra_function_call = true; + /* + * For the impact on the stack, make an intra-function + * call behaves like a push of an immediate value (the + * return address). + */ + insn->stack_op.src.type = OP_SRC_CONST; + insn->stack_op.dest.type = OP_DEST_PUSH; + } + + return 0; +} + static void mark_rodata(struct objtool_file *file) { struct section *sec; @@ -1344,6 +1399,10 @@ static int decode_sections(struct objtool_file *file) if (ret) return ret; + ret = read_intra_function_call(file); + if (ret) + return ret; + ret = add_call_destinations(file); if (ret) return ret; @@ -2092,7 +2151,8 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, return ret; if (!no_fp && func && !is_fentry_call(insn) && - !has_valid_stack_frame(&state)) { + !has_valid_stack_frame(&state) && + !insn->intra_function_call) { WARN_FUNC("call without frame pointer save/setup", sec, insn->offset); return 1; @@ -2101,6 +2161,17 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, if (dead_end_function(file, insn->call_dest)) return 0; + if (insn->intra_function_call) { + update_insn_state(insn, &state); + ret = validate_branch(file, func, insn, + insn->jump_dest, state); + if (ret) { + if (backtrace) + BT_FUNC("(intra-call)", insn); + return ret; + } + } + break; case INSN_JUMP_CONDITIONAL: diff --git a/tools/objtool/check.h b/tools/objtool/check.h index cffb23d81782..2bd6d2f46baa 100644 --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -35,6 +35,7 @@ struct instruction { unsigned long immediate; unsigned int alt_group; bool dead_end, ignore, hint, save, restore, ignore_alts; + bool intra_function_call; bool retpoline_safe; u8 visited; struct symbol *call_dest; -- 2.18.2