From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756547AbbBCXkp (ORCPT ); Tue, 3 Feb 2015 18:40:45 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:54943 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755218AbbBCXPi (ORCPT ); Tue, 3 Feb 2015 18:15:38 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , Yingjoe Chen , Daniel Lezcano , Arnd Bergmann , Ian Campbell , Mark Rutland Subject: [PATCH 3.18 56/57] clocksource: arch_timer: Only use the virtual counter (CNTVCT) on arm64 Date: Tue, 3 Feb 2015 15:14:47 -0800 Message-Id: <20150203231220.406425295@linuxfoundation.org> X-Mailer: git-send-email 2.2.2 In-Reply-To: <20150203231211.486950145@linuxfoundation.org> References: <20150203231211.486950145@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Catalin Marinas commit d6ad36913083d683aad4e02e53580c995f1a6ede upstream. Commit 0b46b8a718c6 (clocksource: arch_timer: Fix code to use physical timers when requested) introduces the use of physical counters in the ARM architected timer driver. However, he arm64 kernel uses CNTVCT in VDSO. When booting in EL2, the kernel switches to the physical timers to make things easier for KVM but it continues to use the virtual counter both in user and kernel. While in such scenario CNTVCT == CNTPCT (since CNTVOFF is initialised by the kernel to 0), we want to spot firmware bugs corrupting CNTVOFF early (which would affect CNTVCT). Signed-off-by: Catalin Marinas Tested-by: Yingjoe Chen Cc: Daniel Lezcano Signed-off-by: Arnd Bergmann Fixes: 0b46b8a718c6 ("clocksource: arch_timer: Fix code to use physical timers when requested") Cc: Ian Campbell Signed-off-by: Mark Rutland Signed-off-by: Greg Kroah-Hartman --- drivers/clocksource/arm_arch_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -462,7 +462,7 @@ static void __init arch_counter_register /* Register the CP15 based counter if we have one */ if (type & ARCH_CP15_TIMER) { - if (arch_timer_use_virtual) + if (IS_ENABLED(CONFIG_ARM64) || arch_timer_use_virtual) arch_timer_read_counter = arch_counter_get_cntvct; else arch_timer_read_counter = arch_counter_get_cntpct;