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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 461BBECDFB8 for ; Fri, 20 Jul 2018 12:37:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00755206B7 for ; Fri, 20 Jul 2018 12:37:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00755206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389220AbeGTNZI (ORCPT ); Fri, 20 Jul 2018 09:25:08 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45068 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387815AbeGTNZH (ORCPT ); Fri, 20 Jul 2018 09:25:07 -0400 Received: from localhost (LFbn-1-12238-233.w90-92.abo.wanadoo.fr [90.92.53.233]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 9E88BC77; Fri, 20 Jul 2018 12:35:03 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Julien Grall , Mark Rutland , Will Deacon , Marc Zyngier , Catalin Marinas Subject: [PATCH 4.14 84/92] arm64: ssbd: Skip apply_ssbd if not using dynamic mitigation Date: Fri, 20 Jul 2018 14:14:28 +0200 Message-Id: <20180720121422.515356188@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180720121417.206337808@linuxfoundation.org> References: <20180720121417.206337808@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marc Zyngier commit 986372c4367f46b34a3c0f6918d7fb95cbdf39d6 upstream. In order to avoid checking arm64_ssbd_callback_required on each kernel entry/exit even if no mitigation is required, let's add yet another alternative that by default jumps over the mitigation, and that gets nop'ed out if we're doing dynamic mitigation. Think of it as a poor man's static key... Reviewed-by: Julien Grall Reviewed-by: Mark Rutland Acked-by: Will Deacon Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/cpu_errata.c | 14 ++++++++++++++ arch/arm64/kernel/entry.S | 3 +++ 2 files changed, 17 insertions(+) --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -285,6 +285,20 @@ void __init arm64_update_smccc_conduit(s *updptr = cpu_to_le32(insn); } +void __init arm64_enable_wa2_handling(struct alt_instr *alt, + __le32 *origptr, __le32 *updptr, + int nr_inst) +{ + BUG_ON(nr_inst != 1); + /* + * Only allow mitigation on EL1 entry/exit and guest + * ARCH_WORKAROUND_2 handling if the SSBD state allows it to + * be flipped. + */ + if (arm64_get_ssbd_state() == ARM64_SSBD_KERNEL) + *updptr = cpu_to_le32(aarch64_insn_gen_nop()); +} + static void arm64_set_ssbd_mitigation(bool state) { switch (psci_ops.conduit) { --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -142,6 +142,9 @@ alternative_else_nop_endif // to save/restore them if required. .macro apply_ssbd, state, targ, tmp1, tmp2 #ifdef CONFIG_ARM64_SSBD +alternative_cb arm64_enable_wa2_handling + b \targ +alternative_cb_end ldr_this_cpu \tmp2, arm64_ssbd_callback_required, \tmp1 cbz \tmp2, \targ mov w0, #ARM_SMCCC_ARCH_WORKAROUND_2