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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 BA14EC3A59C for ; Fri, 16 Aug 2019 12:26:20 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8CC8820644 for ; Fri, 16 Aug 2019 12:26:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="bPPJbaws" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8CC8820644 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=6X3MJPsxnfL9weSX5kdZzHh+mNLOx5ev5/DNNg/1BKM=; b=bPPJbawsDpdeyjDjCaaOPq6Vvi uEofRbXgufRU65yK0+2Yw6QgrVomr2E5JOeLtcZLiYtGbfR8WKK9T3c50YPtTJ4Z/d4jEb9Uxgb+l O/D8MXP/s+X7rQbA+K3jUtPAmd9Tki2f6iVTd1p57+K+dFi4w6lGi71XSPMhoLH3CAxG6o6qGKMgp /KMcwFYMXeULux6QpGrNOR97LZ5rV4LDD7yU0tQpV4NepvDYFV2H7Z531Jo+eNf64ZwIJZ7MzdVk2 X+tKKaWAq2HkQ0bBVNB0IL9CkLf4dUtQvbLRxPxtiFjdG9MHU1dIdJjT6KUVnCjmZu+Fkv3GHeXpU H8ZWqldg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hybJD-0006mt-Ti; Fri, 16 Aug 2019 12:26:19 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hybHj-0004MZ-Ot for linux-arm-kernel@lists.infradead.org; Fri, 16 Aug 2019 12:24:49 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 147AC360; Fri, 16 Aug 2019 05:24:47 -0700 (PDT) Received: from e121650-lin.cambridge.arm.com (e121650-lin.cambridge.arm.com [10.1.196.120]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CF0CD3F706; Fri, 16 Aug 2019 05:24:45 -0700 (PDT) From: Raphael Gault To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, jpoimboe@redhat.com Subject: [RFC v4 05/18] objtool: special: Adapt special section handling Date: Fri, 16 Aug 2019 13:23:50 +0100 Message-Id: <20190816122403.14994-6-raphael.gault@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190816122403.14994-1-raphael.gault@arm.com> References: <20190816122403.14994-1-raphael.gault@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190816_052448_091078_9567ADF3 X-CRM114-Status: GOOD ( 20.98 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: raph.gault+kdev@gmail.com, peterz@infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, Raphael Gault , julien.thierry.kdev@gmail.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org This patch abstracts the few architecture dependent tests that are perform when handling special section and switch tables. It enables any architecture to ignore a particular CPU feature or not to handle switch tables. Signed-off-by: Raphael Gault --- tools/objtool/arch/arm64/Build | 1 + tools/objtool/arch/arm64/arch_special.c | 22 +++++++++++++++ .../objtool/arch/arm64/include/arch_special.h | 10 +++++-- tools/objtool/arch/x86/Build | 1 + tools/objtool/arch/x86/arch_special.c | 28 +++++++++++++++++++ tools/objtool/arch/x86/include/arch_special.h | 9 ++++++ tools/objtool/check.c | 24 ++++++++++++++-- tools/objtool/special.c | 9 ++---- tools/objtool/special.h | 3 ++ 9 files changed, 96 insertions(+), 11 deletions(-) create mode 100644 tools/objtool/arch/arm64/arch_special.c create mode 100644 tools/objtool/arch/x86/arch_special.c diff --git a/tools/objtool/arch/arm64/Build b/tools/objtool/arch/arm64/Build index bf7a32c2b9e9..3d09be745a84 100644 --- a/tools/objtool/arch/arm64/Build +++ b/tools/objtool/arch/arm64/Build @@ -1,3 +1,4 @@ +objtool-y += arch_special.o objtool-y += decode.o objtool-y += orc_dump.o objtool-y += orc_gen.o diff --git a/tools/objtool/arch/arm64/arch_special.c b/tools/objtool/arch/arm64/arch_special.c new file mode 100644 index 000000000000..a21d28876317 --- /dev/null +++ b/tools/objtool/arch/arm64/arch_special.c @@ -0,0 +1,22 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see . + */ +#include "../../special.h" +#include "arch_special.h" + +void arch_force_alt_path(unsigned short feature, + bool uaccess, + struct special_alt *alt) +{ +} diff --git a/tools/objtool/arch/arm64/include/arch_special.h b/tools/objtool/arch/arm64/include/arch_special.h index 63da775d0581..185103be8a51 100644 --- a/tools/objtool/arch/arm64/include/arch_special.h +++ b/tools/objtool/arch/arm64/include/arch_special.h @@ -30,7 +30,13 @@ #define ALT_ORIG_LEN_OFFSET 10 #define ALT_NEW_LEN_OFFSET 11 -#define X86_FEATURE_POPCNT (4 * 32 + 23) -#define X86_FEATURE_SMAP (9 * 32 + 20) +static inline bool arch_should_ignore_feature(unsigned short feature) +{ + return false; +} +static inline bool arch_support_switch_table(void) +{ + return false; +} #endif /* _ARM64_ARCH_SPECIAL_H */ diff --git a/tools/objtool/arch/x86/Build b/tools/objtool/arch/x86/Build index 1f11b45999d0..63e167775bc8 100644 --- a/tools/objtool/arch/x86/Build +++ b/tools/objtool/arch/x86/Build @@ -1,3 +1,4 @@ +objtool-y += arch_special.o objtool-y += decode.o objtool-y += orc_dump.o objtool-y += orc_gen.o diff --git a/tools/objtool/arch/x86/arch_special.c b/tools/objtool/arch/x86/arch_special.c new file mode 100644 index 000000000000..6583a1770bb2 --- /dev/null +++ b/tools/objtool/arch/x86/arch_special.c @@ -0,0 +1,28 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see . + */ +#include "../../special.h" +#include "arch_special.h" + +void arch_force_alt_path(unsigned short feature, + bool uaccess, + struct special_alt *alt) +{ + if (feature == X86_FEATURE_SMAP) { + if (uaccess) + alt->skip_orig = true; + else + alt->skip_alt = true; + } +} diff --git a/tools/objtool/arch/x86/include/arch_special.h b/tools/objtool/arch/x86/include/arch_special.h index 424ce47013e3..fce2b1193194 100644 --- a/tools/objtool/arch/x86/include/arch_special.h +++ b/tools/objtool/arch/x86/include/arch_special.h @@ -33,4 +33,13 @@ #define X86_FEATURE_POPCNT (4 * 32 + 23) #define X86_FEATURE_SMAP (9 * 32 + 20) +static inline bool arch_should_ignore_feature(unsigned short feature) +{ + return feature == X86_FEATURE_POPCNT; +} + +static inline bool arch_support_switch_table(void) +{ + return true; +} #endif /* _X86_ARCH_SPECIAL_H */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 30e147391dcb..4af6422d3428 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -729,7 +729,7 @@ static int handle_group_alt(struct objtool_file *file, last_orig_insn = insn; } - if (next_insn_same_sec(file, last_orig_insn)) { + if (last_orig_insn && next_insn_same_sec(file, last_orig_insn)) { fake_jump = malloc(sizeof(*fake_jump)); if (!fake_jump) { WARN("malloc failed"); @@ -1061,6 +1061,26 @@ static struct rela *find_jump_table(struct objtool_file *file, table_rela = find_rela_by_dest(table_sec, table_offset); if (!table_rela) continue; + /* + * If we are on arm64 architecture, we now that we + * are in presence of a switch table thanks to + * the `br ` insn. but we can't retrieve it yet. + * So we just ignore unreachable for this file. + */ + if (!arch_support_switch_table()) { + file->ignore_unreachables = true; + return NULL; + } + + rodata_rela = find_rela_by_dest(rodata_sec, table_offset); + if (rodata_rela) { + /* + * Use of RIP-relative switch jumps is quite rare, and + * indicates a rare GCC quirk/bug which can leave dead + * code behind. + */ + if (text_rela->type == R_X86_64_PC32) + file->ignore_unreachables = true; /* * Use of RIP-relative switch jumps is quite rare, and @@ -1864,7 +1884,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, insn = first; sec = insn->sec; - if (insn->alt_group && list_empty(&insn->alts)) { + if (!insn->visited && insn->alt_group && list_empty(&insn->alts)) { WARN_FUNC("don't know how to handle branch to middle of alternative instruction group", sec, insn->offset); return 1; diff --git a/tools/objtool/special.c b/tools/objtool/special.c index b8ccee1b5382..7a0092d6e5b3 100644 --- a/tools/objtool/special.c +++ b/tools/objtool/special.c @@ -81,7 +81,7 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry, * feature path which is a "very very small percentage of * machines". */ - if (feature == X86_FEATURE_POPCNT) + if (arch_should_ignore_feature(feature)) alt->skip_orig = true; /* @@ -93,12 +93,7 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry, * find paths that see the STAC but take the NOP instead of * CLAC and the other way around. */ - if (feature == X86_FEATURE_SMAP) { - if (uaccess) - alt->skip_orig = true; - else - alt->skip_alt = true; - } + arch_force_alt_path(feature, uaccess, alt); } orig_rela = find_rela_by_dest(sec, offset + entry->orig); diff --git a/tools/objtool/special.h b/tools/objtool/special.h index 35061530e46e..90626a7e41cf 100644 --- a/tools/objtool/special.h +++ b/tools/objtool/special.h @@ -27,5 +27,8 @@ struct special_alt { }; int special_get_alts(struct elf *elf, struct list_head *alts); +void arch_force_alt_path(unsigned short feature, + bool uaccess, + struct special_alt *alt); #endif /* _SPECIAL_H */ -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel