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 48E1FC43334 for ; Tue, 12 Jul 2022 18:58:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235078AbiGLS66 (ORCPT ); Tue, 12 Jul 2022 14:58:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234550AbiGLS6F (ORCPT ); Tue, 12 Jul 2022 14:58:05 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3AC5DD236; Tue, 12 Jul 2022 11:47:36 -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 ams.source.kernel.org (Postfix) with ESMTPS id A8756B81BAC; Tue, 12 Jul 2022 18:47:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17FA3C3411C; Tue, 12 Jul 2022 18:47:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657651654; bh=6/pAjNrYduXQcYk5rPNhzoaKv6P80lxhDM57Mcardm0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hPRVtdF80iwVzA6XC+oSKSS0HHjXDYNni0if3QLegYg6ZQPNNo6fyJ8u3pAZBrpf9 jx61JbI5+Lti/yRXlR88i3dNdqzYoWcvtydGO/6CoEvURyHRqGA9KFiuW4zQm3yzyD QAOC9HrUWecknr/PcBPKjZ+OucOXfOnI/WZDnNgc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Borislav Petkov , Josh Poimboeuf , Alexei Starovoitov , Thadeu Lima de Souza Cascardo Subject: [PATCH 5.15 06/78] objtool: Explicitly avoid self modifying code in .altinstr_replacement Date: Tue, 12 Jul 2022 20:38:36 +0200 Message-Id: <20220712183239.097913627@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220712183238.844813653@linuxfoundation.org> References: <20220712183238.844813653@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: Peter Zijlstra commit dd003edeffa3cb87bc9862582004f405d77d7670 upstream. Assume ALTERNATIVE()s know what they're doing and do not change, or cause to change, instructions in .altinstr_replacement sections. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Borislav Petkov Acked-by: Josh Poimboeuf Tested-by: Alexei Starovoitov Link: https://lore.kernel.org/r/20211026120309.722511775@infradead.org [cascardo: context adjustment] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman --- tools/objtool/check.c | 43 ++++++++++++++++++++++++++++++++----------- 1 file changed, 32 insertions(+), 11 deletions(-) --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -840,18 +840,27 @@ static void remove_insn_ops(struct instr } } -static void add_call_dest(struct objtool_file *file, struct instruction *insn, - struct symbol *dest, bool sibling) +static void annotate_call_site(struct objtool_file *file, + struct instruction *insn, bool sibling) { struct reloc *reloc = insn_reloc(file, insn); + struct symbol *sym = insn->call_dest; - insn->call_dest = dest; - if (!dest) + if (!sym) + sym = reloc->sym; + + /* + * Alternative replacement code is just template code which is + * sometimes copied to the original instruction. For now, don't + * annotate it. (In the future we might consider annotating the + * original instruction if/when it ever makes sense to do so.) + */ + if (!strcmp(insn->sec->name, ".altinstr_replacement")) return; - if (insn->call_dest->static_call_tramp) { - list_add_tail(&insn->call_node, - &file->static_call_list); + if (sym->static_call_tramp) { + list_add_tail(&insn->call_node, &file->static_call_list); + return; } /* @@ -859,7 +868,7 @@ static void add_call_dest(struct objtool * so they need a little help, NOP out any KCOV calls from noinstr * text. */ - if (insn->sec->noinstr && insn->call_dest->kcov) { + if (insn->sec->noinstr && sym->kcov) { if (reloc) { reloc->type = R_NONE; elf_write_reloc(file->elf, reloc); @@ -881,9 +890,11 @@ static void add_call_dest(struct objtool */ insn->retpoline_safe = true; } + + return; } - if (mcount && insn->call_dest->fentry) { + if (mcount && sym->fentry) { if (sibling) WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset); @@ -898,9 +909,17 @@ static void add_call_dest(struct objtool insn->type = INSN_NOP; - list_add_tail(&insn->mcount_loc_node, - &file->mcount_loc_list); + list_add_tail(&insn->mcount_loc_node, &file->mcount_loc_list); + return; } +} + +static void add_call_dest(struct objtool_file *file, struct instruction *insn, + struct symbol *dest, bool sibling) +{ + insn->call_dest = dest; + if (!dest) + return; /* * Whatever stack impact regular CALLs have, should be undone @@ -910,6 +929,8 @@ static void add_call_dest(struct objtool * are converted to JUMP, see read_intra_function_calls(). */ remove_insn_ops(insn); + + annotate_call_site(file, insn, sibling); } /*