From patchwork Wed Dec 10 11:02:09 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 5468031 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id AFD59BEEA8 for ; Wed, 10 Dec 2014 11:04:42 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C946920125 for ; Wed, 10 Dec 2014 11:04:40 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E69B920121 for ; Wed, 10 Dec 2014 11:04:39 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xyf2e-0006RA-JQ; Wed, 10 Dec 2014 11:02:48 +0000 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xyf2b-0006Jo-7X for linux-arm-kernel@lists.infradead.org; Wed, 10 Dec 2014 11:02:45 +0000 Received: from foss-smtp-na-1.foss.arm.com (unknown [10.80.61.8]) by foss-mx-na.foss.arm.com (Postfix) with ESMTP id 7C11EAE; Wed, 10 Dec 2014 05:02:19 -0600 (CST) Received: from collaborate-mta1.arm.com (highbank-bc01-b06.austin.arm.com [10.112.81.134]) by foss-smtp-na-1.foss.arm.com (Postfix) with ESMTP id 45A395FAD7; Wed, 10 Dec 2014 05:02:11 -0600 (CST) Received: from e104818-lin.cambridge.arm.com (e104818-lin.cambridge.arm.com [10.1.203.148]) by collaborate-mta1.arm.com (Postfix) with ESMTP id 7396D13F630; Wed, 10 Dec 2014 05:02:10 -0600 (CST) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] clocksource: arch_timer: Only use the virtual counter (CNTVCT) on arm64 Date: Wed, 10 Dec 2014 11:02:09 +0000 Message-Id: <1418209329-28615-1-git-send-email-catalin.marinas@arm.com> X-Mailer: git-send-email 2.1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141210_030245_283528_F9DF7942 X-CRM114-Status: UNSURE ( 9.84 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.0 (/) Cc: Daniel Lezcano , Will Deacon X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- Daniel, Do you plan to take this patch and push into mainline (ideally before -rc1)? Otherwise we can push it via the arm64 tree. Thanks, Catalin drivers/clocksource/arm_arch_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 6a79fc4f900c..095c1774592c 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -462,7 +462,7 @@ static void __init arch_counter_register(unsigned type) /* 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;