From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932331AbdGURSo (ORCPT ); Fri, 21 Jul 2017 13:18:44 -0400 Received: from foss.arm.com ([217.140.101.70]:38910 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754550AbdGURPu (ORCPT ); Fri, 21 Jul 2017 13:15:50 -0400 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Mark Rutland , Russell King , Catalin Marinas , Will Deacon , Daniel Lezcano , Thomas Gleixner Subject: [PATCH 01/16] arm64: Use arch_timer_get_rate when trapping CNTFRQ_EL0 Date: Fri, 21 Jul 2017 18:15:27 +0100 Message-Id: <20170721171542.27639-2-marc.zyngier@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170721171542.27639-1-marc.zyngier@arm.com> References: <20170721171542.27639-1-marc.zyngier@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In an ideal world, CNTFRQ_EL0 always contains the timer frequency for the kernel to use. Sadly, we get quite a few broken systems where the firmware authors cannot be bothered to program that register on all CPUs, and rely on DT to provide that frequency. So when trapping CNTFRQ_EL0, make sure to return the actual rate (as known by the kernel), and not CNTFRQ_EL0. Acked-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index c7c7088097be..b02295673216 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -519,7 +519,7 @@ static void cntfrq_read_handler(unsigned int esr, struct pt_regs *regs) { int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT; - pt_regs_write_reg(regs, rt, read_sysreg(cntfrq_el0)); + pt_regs_write_reg(regs, rt, arch_timer_get_rate()); regs->pc += 4; } -- 2.11.0