From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id 417A56B0261 for ; Mon, 1 Jan 2018 09:28:44 -0500 (EST) Received: by mail-wm0-f70.google.com with SMTP id p190so13747055wmd.0 for ; Mon, 01 Jan 2018 06:28:44 -0800 (PST) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id j32si26076816wre.435.2018.01.01.06.28.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 01 Jan 2018 06:28:43 -0800 (PST) From: Greg Kroah-Hartman Subject: [PATCH 4.4 30/63] x86/mm: Add the nopcid boot option to turn off PCID Date: Mon, 1 Jan 2018 15:24:48 +0100 Message-Id: <20180101140047.694473930@linuxfoundation.org> In-Reply-To: <20180101140042.456380281@linuxfoundation.org> References: <20180101140042.456380281@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Nadav Amit , Borislav Petkov , Thomas Gleixner , Andrew Morton , Arjan van de Ven , Borislav Petkov , Dave Hansen , Linus Torvalds , Mel Gorman , Peter Zijlstra , Rik van Riel , linux-mm@kvack.org, Ingo Molnar , Hugh Dickins 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski commit 0790c9aad84901ca1bdc14746175549c8b5da215 upstream. The parameter is only present on x86_64 systems to save a few bytes, as PCID is always disabled on x86_32. Signed-off-by: Andy Lutomirski Reviewed-by: Nadav Amit Reviewed-by: Borislav Petkov Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dave Hansen Cc: Linus Torvalds Cc: Mel Gorman Cc: Peter Zijlstra Cc: Rik van Riel Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/8bbb2e65bcd249a5f18bfb8128b4689f08ac2b60.1498751203.git.luto@kernel.org Signed-off-by: Ingo Molnar Cc: Hugh Dickins Signed-off-by: Greg Kroah-Hartman --- Documentation/kernel-parameters.txt | 2 ++ arch/x86/kernel/cpu/common.c | 18 ++++++++++++++++++ 2 files changed, 20 insertions(+) --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2555,6 +2555,8 @@ bytes respectively. Such letter suffixes nopat [X86] Disable PAT (page attribute table extension of pagetables) support. + nopcid [X86-64] Disable the PCID cpu feature. + norandmaps Don't use address space randomization. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -162,6 +162,24 @@ static int __init x86_mpx_setup(char *s) } __setup("nompx", x86_mpx_setup); +#ifdef CONFIG_X86_64 +static int __init x86_pcid_setup(char *s) +{ + /* require an exact match without trailing characters */ + if (strlen(s)) + return 0; + + /* do not emit a message if the feature is not present */ + if (!boot_cpu_has(X86_FEATURE_PCID)) + return 1; + + setup_clear_cpu_cap(X86_FEATURE_PCID); + pr_info("nopcid: PCID feature disabled\n"); + return 1; +} +__setup("nopcid", x86_pcid_setup); +#endif + static int __init x86_noinvpcid_setup(char *s) { /* noinvpcid doesn't accept parameters */ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org