From patchwork Fri May 18 09:46:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Murzin X-Patchwork-Id: 10409299 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 19E7F602C2 for ; Fri, 18 May 2018 09:51:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0932D285A2 for ; Fri, 18 May 2018 09:51:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F22EA288CA; Fri, 18 May 2018 09:51:52 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 737B0285A2 for ; Fri, 18 May 2018 09:51:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=ZoDPxkzOVHVsNhg8Lrg9UZ1xpQoBm7riWmOYj+f07I4=; b=uVvViVbYeWTXbubhHgeDWNgOn4 Z1nVh26YqNuc+DOWXFvYzONhJkq7ndwg4Ugn7ciDzWIy/JZhucaWdb7ZqMTqo0DNaE4n8A4V/BxtB u2ecLw56whNV5PMZq6ERnxa7zKFhmN93teNuXgzArrXA8S8TV1LHhHLarhL6jJudtH5wkrtrjueBQ SgOTqj9iXUA05eTGAoT3T/IoewcsVe/a0haJbZsgyHsXpjecCWdvmBP5MliDuLgHzhThB9iLNmbko 5ZZ4oL733UM76kHi6232nZF/pUn4zC06TAOfF1Uy9RPzMiAehwiuyCC18pK0oiLPmJ+lIj+jJGp2s cC59+GBg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fJc34-0002ev-7s; Fri, 18 May 2018 09:51:42 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fJby9-0007ro-PE for linux-arm-kernel@lists.infradead.org; Fri, 18 May 2018 09:46:56 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4A543165C; Fri, 18 May 2018 02:46:28 -0700 (PDT) Received: from bc-d4-3-15.euhpc.arm.com. (bc-d4-3-15.euhpc.arm.com [10.6.4.213]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 60E6A3F53D; Fri, 18 May 2018 02:46:27 -0700 (PDT) From: Vladimir Murzin To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 3/3] arm64: Introduce command line parameter to disable CNP Date: Fri, 18 May 2018 10:46:05 +0100 Message-Id: <1526636765-11289-4-git-send-email-vladimir.murzin@arm.com> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1526636765-11289-1-git-send-email-vladimir.murzin@arm.com> References: <1526636765-11289-1-git-send-email-vladimir.murzin@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180518_024637_943444_D64EEEAF X-CRM114-Status: GOOD ( 12.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, james.morse@arm.com, julien.thierry@arm.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP There are cases when activating of Common Not Private (CNP) feature might not be desirable; this patch allows to forcefully disable CNP even it is supported by hardware. Signed-off-by: Vladimir Murzin --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ arch/arm64/kernel/cpufeature.c | 11 ++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1d1d53f..181ecca 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2603,6 +2603,10 @@ noclflush [BUGS=X86] Don't use the CLFLUSH instruction + nocnp [ARM64] + Disable CNP (Common not Private translations) + even if it is supported by processor. + nodelayacct [KNL] Disable per-task delay accounting nodsp [SH] Disable hardware DSP at boot time. diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 78de218..80fe8fa 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -826,6 +826,15 @@ static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry, int _ MIDR_CPU_VAR_REV(1, MIDR_REVISION_MASK)); } +static bool nocnp; + +static int __init early_nocnp(char *p) +{ + nocnp = true; + return 0; +} +early_param("nocnp", early_nocnp); + static bool __maybe_unused has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope) { @@ -833,7 +842,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope) if (elfcorehdr_size) return false; #endif - return has_cpuid_feature(entry, scope); + return has_cpuid_feature(entry, scope) && !nocnp; } static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused)