From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57703 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932912AbbIZVHj (ORCPT ); Sat, 26 Sep 2015 17:07:39 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Zyngier , Will Deacon Subject: [PATCH 4.1 021/159] arm64: head.S: initialise mdcr_el2 in el2_setup Date: Sat, 26 Sep 2015 13:54:27 -0700 Message-Id: <20150926205314.690812626@linuxfoundation.org> In-Reply-To: <20150926205313.363686083@linuxfoundation.org> References: <20150926205313.363686083@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: stable-owner@vger.kernel.org List-ID: 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon commit d10bcd473301888f957ec4b6b12aa3621be78d59 upstream. When entering the kernel at EL2, we fail to initialise the MDCR_EL2 register which controls debug access and PMU capabilities at EL1. This patch ensures that the register is initialised so that all traps are disabled and all the PMU counters are available to the host. When a guest is scheduled, KVM takes care to configure trapping appropriately. Acked-by: Marc Zyngier Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/head.S | 5 +++++ 1 file changed, 5 insertions(+) --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -565,6 +565,11 @@ CPU_LE( movk x0, #0x30d0, lsl #16 ) // C msr hstr_el2, xzr // Disable CP15 traps to EL2 #endif + /* EL2 debug */ + mrs x0, pmcr_el0 // Disable debug access traps + ubfx x0, x0, #11, #5 // to EL2 and allow access to + msr mdcr_el2, x0 // all PMU counters from EL1 + /* Stage-2 translation */ msr vttbr_el2, xzr