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=-8.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 DFCC3C04A6B for ; Tue, 7 May 2019 02:41:58 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6558C206A3 for ; Tue, 7 May 2019 02:41:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6558C206A3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=informatik.wtf Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44ykQX2lPFzDqNv for ; Tue, 7 May 2019 12:41:56 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 44ykP65rrDzDqFB for ; Tue, 7 May 2019 12:40:42 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=informatik.wtf Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by bilbo.ozlabs.org (Postfix) with ESMTP id 44ykP63MqKz8t9Z for ; Tue, 7 May 2019 12:40:42 +1000 (AEST) Received: by ozlabs.org (Postfix) id 44ykP63BNKz9sBV; Tue, 7 May 2019 12:40:42 +1000 (AEST) Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=informatik.wtf (client-ip=198.54.122.46; helo=new-02-2.privateemail.com; envelope-from=cmr@informatik.wtf; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=informatik.wtf Received: from NEW-02-2.privateemail.com (new-02-2.privateemail.com [198.54.122.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44ykP61JY9z9s9y for ; Tue, 7 May 2019 12:40:41 +1000 (AEST) Received: from MTA-08-1.privateemail.com (unknown [10.20.147.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by NEW-02.privateemail.com (Postfix) with ESMTPS id DFD416151E; Tue, 7 May 2019 02:40:39 +0000 (UTC) Received: from MTA-08.privateemail.com (localhost [127.0.0.1]) by MTA-08.privateemail.com (Postfix) with ESMTP id C37FA60051; Mon, 6 May 2019 22:40:39 -0400 (EDT) Received: from wrwlf0000.attlocal.net (unknown [10.20.151.244]) by MTA-08.privateemail.com (Postfix) with ESMTPA id 4010960048; Tue, 7 May 2019 02:40:39 +0000 (UTC) From: "Christopher M. Riedl" To: linuxppc-dev@ozlabs.org Subject: [PATCH v2] powerpc/64s: support nospectre_v2 cmdline option Date: Mon, 6 May 2019 21:43:21 -0500 Message-Id: <20190507024321.22281-1-cmr@informatik.wtf> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Virus-Scanned: ClamAV using ClamSMTP X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Christopher M. Riedl" , ajd@linux.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Add support for disabling the kernel implemented spectre v2 mitigation (count cache flush on context switch) via the nospectre_v2 cmdline option. Suggested-by: Michael Ellerman Signed-off-by: Christopher M. Riedl --- v1->v2: add call to toggle_count_cache_flush(false) arch/powerpc/kernel/security.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c index b33bafb8fcea..d775da9b9227 100644 --- a/arch/powerpc/kernel/security.c +++ b/arch/powerpc/kernel/security.c @@ -28,7 +28,7 @@ static enum count_cache_flush_type count_cache_flush_type = COUNT_CACHE_FLUSH_NO bool barrier_nospec_enabled; static bool no_nospec; static bool btb_flush_enabled; -#ifdef CONFIG_PPC_FSL_BOOK3E +#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64) static bool no_spectrev2; #endif @@ -106,7 +106,7 @@ static __init int barrier_nospec_debugfs_init(void) device_initcall(barrier_nospec_debugfs_init); #endif /* CONFIG_DEBUG_FS */ -#ifdef CONFIG_PPC_FSL_BOOK3E +#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64) static int __init handle_nospectre_v2(char *p) { no_spectrev2 = true; @@ -114,6 +114,9 @@ static int __init handle_nospectre_v2(char *p) return 0; } early_param("nospectre_v2", handle_nospectre_v2); +#endif /* CONFIG_PPC_FSL_BOOK3E || CONFIG_PPC_BOOK3S_64 */ + +#ifdef CONFIG_PPC_FSL_BOOK3E void setup_spectre_v2(void) { if (no_spectrev2) @@ -391,6 +394,15 @@ static void toggle_count_cache_flush(bool enable) void setup_count_cache_flush(void) { + if (no_spectrev2) { + if (security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED) + || security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED)) + pr_warn("Spectre v2 mitigations not under software control, can't disable\n"); + + toggle_count_cache_flush(false); + return; + } + toggle_count_cache_flush(true); } -- 2.21.0