Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162514Ab3DEU5c (ORCPT ); Fri, 5 Apr 2013 16:57:32 -0400 Received: from wolverine02.qualcomm.com ([199.106.114.251]:37314 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162356Ab3DEU5b (ORCPT ); Fri, 5 Apr 2013 16:57:31 -0400 X-IronPort-AV: E=Sophos;i="4.87,416,1363158000"; d="scan'208";a="36286248" From: Stephen Boyd To: John Stultz , Thomas Gleixner Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Mark Rutland , Marc Zyngier Subject: [PATCHv2] ARM: arch_timer: Silence debug preempt warnings Date: Fri, 5 Apr 2013 13:57:29 -0700 Message-Id: <1365195449-6755-1-git-send-email-sboyd@codeaurora.org> X-Mailer: git-send-email 1.8.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2175 Lines: 60 Hot-plugging with CONFIG_DEBUG_PREEMPT=y on a device with arm architected timers causes a slew of "using smp_processor_id() in preemptible" warnings: BUG: using smp_processor_id() in preemptible [00000000] code: sh/111 caller is arch_timer_cpu_notify+0x14/0xc8 This happens because sometimes the cpu notifier, arch_timer_cpu_notify(), is called in preemptible context and other times in non-preemptible context but we use this_cpu_ptr() to retrieve the clockevent in all cases. We're only going to actually use the pointer in non-preemptible context though, so push the this_cpu_ptr() access down into the cases to force the checks to occur only in non-preemptible contexts. Cc: Mark Rutland Cc: Marc Zyngier Signed-off-by: Stephen Boyd --- Changes since v1: * Pushed down this_cpu_ptr and added a comment drivers/clocksource/arm_arch_timer.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index d7ad425..a65a710 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -248,14 +248,16 @@ static void __cpuinit arch_timer_stop(struct clock_event_device *clk) static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { - struct clock_event_device *evt = this_cpu_ptr(arch_timer_evt); - + /* + * Grab cpu pointer in each case to avoid spurious + * preemptible warnings + */ switch (action & ~CPU_TASKS_FROZEN) { case CPU_STARTING: - arch_timer_setup(evt); + arch_timer_setup(this_cpu_ptr(arch_timer_evt)); break; case CPU_DYING: - arch_timer_stop(evt); + arch_timer_stop(this_cpu_ptr(arch_timer_evt)); break; } -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/