From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 26A8F5394 for ; Fri, 18 Mar 2022 23:08:58 +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> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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