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 5383EC4332F for ; Fri, 22 Apr 2022 10:35:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1446745AbiDVKiM (ORCPT ); Fri, 22 Apr 2022 06:38:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1446690AbiDVKhz (ORCPT ); Fri, 22 Apr 2022 06:37:55 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 699EB267D; Fri, 22 Apr 2022 03:35:02 -0700 (PDT) Date: Fri, 22 Apr 2022 10:34:59 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1650623701; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oiEYmoZjIQrxdFGwC+0CzfQvHyMPdpawUJRLao7DDa4=; b=eVfOyHIVmsugcS3svJ0So0tIVmSoxp5WDCrQjvoPDXz9dzvmvwWDtmyK+eZI/+7M5vuV7H I5hkLhJZr0Bu+/wGSCsukLTiPoSPK86o8GDEVS30M17SRIvJwNTy865u5kut7V5yOIdFaI ldJgGNj8YHNTESWZ8Uogzq5oLk3rQGJeoE7aKV1MRME1VionjluxqgrOaiWM07rcpFy3Pa CX97EKm5RImWxzBQeqPACxxnVLw5d7BHYaw8X8vVbwQO3x7N+sSrHsf7fvQrmkVZjvZwB9 /2Wiq0zANlhHC4w09fslF/NUMlmAd5ownsGBT88NWvqvLGUeffgGAxPd1uN9xQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1650623701; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oiEYmoZjIQrxdFGwC+0CzfQvHyMPdpawUJRLao7DDa4=; b=NFeAERcHYlEGG1jPZDXVjGCb/ZdSud6Q/SYZTJzbYs73GVIKKm7kn4XJuA8NJ2fyRxMJTo FAczuZ6M/SJ181DQ== From: "tip-bot2 for Josh Poimboeuf" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: objtool/core] objtool: Make jump label hack optional Cc: Josh Poimboeuf , "Peter Zijlstra (Intel)" , Miroslav Benes , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <3bdcbfdd27ecb01ddec13c04bdf756a583b13d24.1650300597.git.jpoimboe@redhat.com> References: <3bdcbfdd27ecb01ddec13c04bdf756a583b13d24.1650300597.git.jpoimboe@redhat.com> MIME-Version: 1.0 Message-ID: <165062369992.4207.4944845531831968750.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the objtool/core branch of tip: Commit-ID: 4ab7674f5951ac6a8ac4fa8828090edb64a4771f Gitweb: https://git.kernel.org/tip/4ab7674f5951ac6a8ac4fa8828090edb64a4771f Author: Josh Poimboeuf AuthorDate: Mon, 18 Apr 2022 09:50:39 -07:00 Committer: Peter Zijlstra CommitterDate: Fri, 22 Apr 2022 12:32:04 +02:00 objtool: Make jump label hack optional Objtool secretly does a jump label hack to overcome the limitations of the toolchain. Make the hack explicit (and optional for other arches) by turning it into a cmdline option and kernel config option. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Link: https://lkml.kernel.org/r/3bdcbfdd27ecb01ddec13c04bdf756a583b13d24.1650300597.git.jpoimboe@redhat.com --- arch/Kconfig | 4 +++- arch/x86/Kconfig | 1 +- arch/x86/include/asm/jump_label.h | 6 ++-- scripts/Makefile.build | 1 +- scripts/link-vmlinux.sh | 4 +++- tools/objtool/builtin-check.c | 37 ++++++++++++++++++------ tools/objtool/check.c | 2 +- tools/objtool/include/objtool/builtin.h | 1 +- 8 files changed, 44 insertions(+), 12 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 04cdef1..9dce6d6 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -46,6 +46,7 @@ config JUMP_LABEL bool "Optimize very unlikely/likely branches" depends on HAVE_ARCH_JUMP_LABEL depends on CC_HAS_ASM_GOTO + select OBJTOOL if HAVE_JUMP_LABEL_HACK help This option enables a transparent branch optimization that makes certain almost-always-true or almost-always-false branch @@ -1031,6 +1032,9 @@ config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT config HAVE_OBJTOOL bool +config HAVE_JUMP_LABEL_HACK + bool + config HAVE_STACK_VALIDATION bool help diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 43e26ee..26d012f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -212,6 +212,7 @@ config X86 select HAVE_IOREMAP_PROT select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 select HAVE_IRQ_TIME_ACCOUNTING + select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL select HAVE_KERNEL_BZIP2 select HAVE_KERNEL_GZIP select HAVE_KERNEL_LZ4 diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h index 3ce0e67..071572e 100644 --- a/arch/x86/include/asm/jump_label.h +++ b/arch/x86/include/asm/jump_label.h @@ -20,7 +20,7 @@ _ASM_PTR "%c0 + %c1 - .\n\t" \ ".popsection \n\t" -#ifdef CONFIG_OBJTOOL +#ifdef CONFIG_HAVE_JUMP_LABEL_HACK static __always_inline bool arch_static_branch(struct static_key *key, bool branch) { @@ -34,7 +34,7 @@ l_yes: return true; } -#else /* !CONFIG_OBJTOOL */ +#else /* !CONFIG_HAVE_JUMP_LABEL_HACK */ static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch) { @@ -48,7 +48,7 @@ l_yes: return true; } -#endif /* CONFIG_OBJTOOL */ +#endif /* CONFIG_HAVE_JUMP_LABEL_HACK */ static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch) { diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 3f20d56..f1d2c2e 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -227,6 +227,7 @@ ifdef CONFIG_OBJTOOL objtool := $(objtree)/tools/objtool/objtool objtool_args = \ + $(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label) \ $(if $(CONFIG_X86_KERNEL_IBT), --lto --ibt) \ $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \ $(if $(CONFIG_UNWINDER_ORC), --orc) \ diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 33f14fe..fa1f168 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -117,6 +117,10 @@ objtool_link() # Don't perform vmlinux validation unless explicitly requested, # but run objtool on vmlinux.o now that we have an object file. + if is_enabled CONFIG_HAVE_JUMP_LABEL_HACK; then + objtoolopt="${objtoolopt} --hacks=jump_label" + fi + if is_enabled CONFIG_X86_KERNEL_IBT; then objtoolopt="${objtoolopt} --ibt" fi diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index c8c4d2b..b2c626d 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -31,8 +31,28 @@ static int parse_dump(const struct option *opt, const char *str, int unset) return -1; } +static int parse_hacks(const struct option *opt, const char *str, int unset) +{ + bool found = false; + + /* + * Use strstr() as a lazy method of checking for comma-separated + * options. + * + * No string provided == enable all options. + */ + + if (!str || strstr(str, "jump_label")) { + opts.hack_jump_label = true; + found = true; + } + + return found ? 0 : -1; +} + const struct option check_options[] = { OPT_GROUP("Actions:"), + OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label", "patch toolchain bugs/limitations", parse_hacks), OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"), OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"), OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"), @@ -87,14 +107,15 @@ int cmd_parse_options(int argc, const char **argv, const char * const usage[]) static bool opts_valid(void) { - if (opts.ibt || - opts.mcount || - opts.noinstr || - opts.orc || - opts.retpoline || - opts.sls || - opts.stackval || - opts.static_call || + if (opts.hack_jump_label || + opts.ibt || + opts.mcount || + opts.noinstr || + opts.orc || + opts.retpoline || + opts.sls || + opts.stackval || + opts.static_call || opts.uaccess) { if (opts.dump_orc) { fprintf(stderr, "--dump can't be combined with other options\n"); diff --git a/tools/objtool/check.c b/tools/objtool/check.c index b9ac351..d157978 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1592,7 +1592,7 @@ static int handle_jump_alt(struct objtool_file *file, return -1; } - if (special_alt->key_addend & 2) { + if (opts.hack_jump_label && special_alt->key_addend & 2) { struct reloc *reloc = insn_reloc(file, orig_insn); if (reloc) { diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h index dc47572..c6acf05 100644 --- a/tools/objtool/include/objtool/builtin.h +++ b/tools/objtool/include/objtool/builtin.h @@ -12,6 +12,7 @@ extern const struct option check_options[]; struct opts { /* actions: */ bool dump_orc; + bool hack_jump_label; bool ibt; bool mcount; bool noinstr;