Return-Path: Received: from mail.kernel.org ([198.145.29.99]:45684 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030878AbeEXKBG (ORCPT ); Thu, 24 May 2018 06:01:06 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Martin Schwidefsky Subject: [PATCH 4.16 051/161] s390: report spectre mitigation via syslog Date: Thu, 24 May 2018 11:37:56 +0200 Message-Id: <20180524093024.568592676@linuxfoundation.org> In-Reply-To: <20180524093018.331893860@linuxfoundation.org> References: <20180524093018.331893860@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky [ Upstream commit bc035599718412cfba9249aa713f90ef13f13ee9 ] Add a boot message if either of the spectre defenses is active. The message is "Spectre V2 mitigation: execute trampolines." or "Spectre V2 mitigation: limited branch prediction." Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/nospec-branch.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/arch/s390/kernel/nospec-branch.c +++ b/arch/s390/kernel/nospec-branch.c @@ -32,6 +32,16 @@ static int __init nospec_setup_early(cha } early_param("nospec", nospec_setup_early); +static int __init nospec_report(void) +{ + if (IS_ENABLED(CC_USING_EXPOLINE) && !nospec_disable) + pr_info("Spectre V2 mitigation: execute trampolines.\n"); + if (__test_facility(82, S390_lowcore.alt_stfle_fac_list)) + pr_info("Spectre V2 mitigation: limited branch prediction.\n"); + return 0; +} +arch_initcall(nospec_report); + #ifdef CONFIG_EXPOLINE int nospec_disable = IS_ENABLED(CONFIG_EXPOLINE_OFF);