From patchwork Thu Mar 31 18:33:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 555548 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 11100C433FE for ; Thu, 31 Mar 2022 18:34:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235767AbiCaSgh (ORCPT ); Thu, 31 Mar 2022 14:36:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235228AbiCaSgd (ORCPT ); Thu, 31 Mar 2022 14:36:33 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 423C62325FC; Thu, 31 Mar 2022 11:34:45 -0700 (PDT) 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 1325013D5; Thu, 31 Mar 2022 11:34:45 -0700 (PDT) Received: from eglon.cambridge.arm.com (eglon.cambridge.arm.com [10.1.196.218]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 69B2D3F718; Thu, 31 Mar 2022 11:34:44 -0700 (PDT) From: James Morse To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: james.morse@arm.com, catalin.marinas@arm.com Subject: [stable:PATCH v4.14.274 18/27] arm64: entry: Add non-kpti __bp_harden_el1_vectors for mitigations Date: Thu, 31 Mar 2022 19:33:51 +0100 Message-Id: <20220331183400.73183-19-james.morse@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220331183400.73183-1-james.morse@arm.com> References: <20220331183400.73183-1-james.morse@arm.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit aff65393fa1401e034656e349abd655cfe272de0 upstream. kpti is an optional feature, for systems not using kpti a set of vectors for the spectre-bhb mitigations is needed. Add another set of vectors, __bp_harden_el1_vectors, that will be used if a mitigation is needed and kpti is not in use. The EL1 ventries are repeated verbatim as there is no additional work needed for entry from EL1. Reviewed-by: Russell King (Oracle) Reviewed-by: Catalin Marinas Signed-off-by: James Morse --- arch/arm64/kernel/entry.S | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index f50539bdf5be..bf6f4513c81f 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -1025,10 +1025,11 @@ alternative_else_nop_endif .macro tramp_ventry, vector_start, regsize, kpti .align 7 1: - .if \kpti == 1 .if \regsize == 64 msr tpidrro_el0, x30 // Restored in kernel_ventry .endif + + .if \kpti == 1 /* * Defend against branch aliasing attacks by pushing a dummy * entry onto the return stack and using a RET instruction to @@ -1111,6 +1112,37 @@ __entry_tramp_data_start: #endif /* CONFIG_RANDOMIZE_BASE */ #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ +/* + * Exception vectors for spectre mitigations on entry from EL1 when + * kpti is not in use. + */ + .macro generate_el1_vector +.Lvector_start\@: + kernel_ventry 1, sync_invalid // Synchronous EL1t + kernel_ventry 1, irq_invalid // IRQ EL1t + kernel_ventry 1, fiq_invalid // FIQ EL1t + kernel_ventry 1, error_invalid // Error EL1t + + kernel_ventry 1, sync // Synchronous EL1h + kernel_ventry 1, irq // IRQ EL1h + kernel_ventry 1, fiq_invalid // FIQ EL1h + kernel_ventry 1, error_invalid // Error EL1h + + .rept 4 + tramp_ventry .Lvector_start\@, 64, kpti=0 + .endr + .rept 4 + tramp_ventry .Lvector_start\@, 32, kpti=0 + .endr + .endm + + .pushsection ".entry.text", "ax" + .align 11 +ENTRY(__bp_harden_el1_vectors) + generate_el1_vector +END(__bp_harden_el1_vectors) + .popsection + /* * Special system call wrappers. */