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 60611C433EF for ; Fri, 18 Mar 2022 23:09:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241475AbiCRXKX (ORCPT ); Fri, 18 Mar 2022 19:10:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232891AbiCRXKU (ORCPT ); Fri, 18 Mar 2022 19:10:20 -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 7E9C9F8472 for ; Fri, 18 Mar 2022 16:09:00 -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 4624CB825E7 for ; Fri, 18 Mar 2022 23:08:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99547C340F4; Fri, 18 Mar 2022 23:08:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1647644938; bh=yEsoADbptHdI9cYSyIc5JdQzpMyt92hieOpRtvY3XvY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HiMLE0eA6e5GU2iyqUD/QBo0thLHb2ogej7foy+2g4erJkfD2LYKr6hrjE/OytJJ+ OfFPXBvgNfEDqTN/nZCWwq1k+pDrYWzvuCYOFTxZ0nb7raronYXtJLsart9mcVEaW/ OtcwTne91Y3GzbHtJBOKonFemtUXdBXYD2YsK4BAngSKGXr7JXQ57LAjwWiVSqnzMB d3gqaaMeaQlC0udV8a0pX0ksdxNUKuZlNHDvAjoUYHKaSUzrFAFLCkZV7Yf+9tiZmc srRsVnyROCBJROmcmFb7oZ5Hbay+6+N+9FRaNwQghDvY1LKDsv37pkrUx3TZaypOsQ EteMs7Vls+isw== From: Nathan Chancellor To: Peter Zijlstra , x86@kernel.org Cc: Nick Desaulniers , linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Nathan Chancellor Subject: [PATCH 2/2] x86/Kconfig: Only allow CONFIG_X86_KERNEL_IBT with ld.lld >= 14.0.0 Date: Fri, 18 Mar 2022 16:07:47 -0700 Message-Id: <20220318230747.3900772-3-nathan@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220318230747.3900772-1-nathan@kernel.org> References: <20220318230747.3900772-1-nathan@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With CONFIG_X86_KERNEL_IBT=y and a version of ld.lld prior to 14.0.0, there are numerous objtool warnings along the lines of: warning: objtool: .plt+0x6: indirect jump found in RETPOLINE build This is a known issue that has been resolved in ld.lld 14.0.0. Prevent CONFIG_X86_KERNEL_IBT from being selectable when using one of these problematic ld.lld versions. Link: https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f Signed-off-by: Nathan Chancellor --- arch/x86/Kconfig | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 921e4ebda564..87579264aa00 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1875,6 +1875,8 @@ config X86_KERNEL_IBT prompt "Indirect Branch Tracking" bool depends on X86_64 && CC_HAS_IBT && STACK_VALIDATION + # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f + depends on !LD_IS_LLD || LLD_VERSION >= 140000 help Build the kernel with support for Indirect Branch Tracking, a hardware support course-grain forward-edge Control Flow Integrity -- 2.35.1