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 2F371CCA47F for ; Tue, 12 Jul 2022 18:45:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234185AbiGLSpn (ORCPT ); Tue, 12 Jul 2022 14:45:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234291AbiGLSpK (ORCPT ); Tue, 12 Jul 2022 14:45:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D68A9DB2C2; Tue, 12 Jul 2022 11:42:28 -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 73EFDB81B96; Tue, 12 Jul 2022 18:42:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEF5DC3411C; Tue, 12 Jul 2022 18:42:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657651346; bh=XZe6mZDywRYuCTJTB4/Kt7NN12giWZC5dpHCMsUZakg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fpsp3vEoFY6p3C7/Bx/o3sZVMacTkxc/99brFav3Kx62Z4eKfDPuqs249b6FAwHZa vUzAL1sRII2Bm9OwY78mEDDIYTEZoaZoxXkH/x2NXNNf0eExjte1yXCIHAguJ146wO LPeEvKSsEo6AWP0Rkyf1GOUVyjkOExD7gJqOv/jo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stephen Rothwell , Borislav Petkov , "Peter Zijlstra (Intel)" , Josh Poimboeuf , Nathan Chancellor , Ben Hutchings Subject: [PATCH 5.10 041/130] objtool: Teach get_alt_entry() about more relocation types Date: Tue, 12 Jul 2022 20:38:07 +0200 Message-Id: <20220712183248.303544818@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: Peter Zijlstra commit 24ff652573754fe4c03213ebd26b17e86842feb3 upstream. Occasionally objtool encounters symbol (as opposed to section) relocations in .altinstructions. Typically they are the alternatives written by elf_add_alternative() as encountered on a noinstr validation run on vmlinux after having already ran objtool on the individual .o files. Basically this is the counterpart of commit 44f6a7c0755d ("objtool: Fix seg fault with Clang non-section symbols"), because when these new assemblers (binutils now also does this) strip the section symbols, elf_add_reloc_to_insn() is forced to emit symbol based relocations. As such, teach get_alt_entry() about different relocation types. Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls") Reported-by: Stephen Rothwell Reported-by: Borislav Petkov Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Tested-by: Nathan Chancellor Link: https://lore.kernel.org/r/YVWUvknIEVNkPvnP@hirez.programming.kicks-ass.net Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- tools/objtool/special.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-) --- a/tools/objtool/special.c +++ b/tools/objtool/special.c @@ -55,6 +55,24 @@ void __weak arch_handle_alternative(unsi { } +static bool reloc2sec_off(struct reloc *reloc, struct section **sec, unsigned long *off) +{ + switch (reloc->sym->type) { + case STT_FUNC: + *sec = reloc->sym->sec; + *off = reloc->sym->offset + reloc->addend; + return true; + + case STT_SECTION: + *sec = reloc->sym->sec; + *off = reloc->addend; + return true; + + default: + return false; + } +} + static int get_alt_entry(struct elf *elf, struct special_entry *entry, struct section *sec, int idx, struct special_alt *alt) @@ -87,15 +105,12 @@ static int get_alt_entry(struct elf *elf WARN_FUNC("can't find orig reloc", sec, offset + entry->orig); return -1; } - if (orig_reloc->sym->type != STT_SECTION) { - WARN_FUNC("don't know how to handle non-section reloc symbol %s", + if (!reloc2sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off)) { + WARN_FUNC("don't know how to handle reloc symbol type: %s", sec, offset + entry->orig, orig_reloc->sym->name); return -1; } - alt->orig_sec = orig_reloc->sym->sec; - alt->orig_off = orig_reloc->addend; - if (!entry->group || alt->new_len) { new_reloc = find_reloc_by_dest(elf, sec, offset + entry->new); if (!new_reloc) { @@ -112,8 +127,11 @@ static int get_alt_entry(struct elf *elf if (arch_is_retpoline(new_reloc->sym)) return 1; - alt->new_sec = new_reloc->sym->sec; - alt->new_off = (unsigned int)new_reloc->addend; + if (!reloc2sec_off(new_reloc, &alt->new_sec, &alt->new_off)) { + WARN_FUNC("don't know how to handle reloc symbol type: %s", + sec, offset + entry->new, new_reloc->sym->name); + return -1; + } /* _ASM_EXTABLE_EX hack */ if (alt->new_off >= 0x7ffffff0)