From patchwork Sun May 5 22:10:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Christopher M. Riedl" X-Patchwork-Id: 1095592 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44y0cX611rz9s9N for ; Mon, 6 May 2019 08:18:04 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=informatik.wtf Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44y0cX4tDvzDqK1 for ; Mon, 6 May 2019 08:18:04 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org 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 44y0bK2RZFzDqJ3 for ; Mon, 6 May 2019 08:17:01 +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 44y0bH6m5Bz8t4f for ; Mon, 6 May 2019 08:16:59 +1000 (AEST) Received: by ozlabs.org (Postfix) id 44y0bH6LDHz9sB8; Mon, 6 May 2019 08:16:59 +1000 (AEST) Delivered-To: linuxppc-dev@ozlabs.org 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 X-Greylist: delayed 523 seconds by postgrey-1.36 at bilbo; Mon, 06 May 2019 08:16:59 AEST 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 44y0bH16mDz9s9N for ; Mon, 6 May 2019 08:16:58 +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 E3BF5604F4; Sun, 5 May 2019 22:08:14 +0000 (UTC) Received: from MTA-08.privateemail.com (localhost [127.0.0.1]) by MTA-08.privateemail.com (Postfix) with ESMTP id D031560038; Sun, 5 May 2019 18:08:14 -0400 (EDT) Received: from wrwlf0000.attlocal.net (unknown [10.20.151.212]) by MTA-08.privateemail.com (Postfix) with ESMTPA id 6C8DE60033; Sun, 5 May 2019 22:08:14 +0000 (UTC) From: "Christopher M. Riedl" To: linuxppc-dev@ozlabs.org Subject: [PATCH] powerpc/64s: support nospectre_v2 cmdline option Date: Sun, 5 May 2019 17:10:48 -0500 Message-Id: <20190505221048.28212-1-cmr@informatik.wtf> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 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" , andrew.donnellan@au1.ibm.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.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 --- reference: https://github.com/linuxppc/issues/issues/236 arch/powerpc/kernel/security.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c index b33bafb8fcea..f7c34745cd0f 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 +394,13 @@ 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"); + return; + } + toggle_count_cache_flush(true); }