From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751879AbaBYH55 (ORCPT ); Tue, 25 Feb 2014 02:57:57 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:55567 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750708AbaBYH5z (ORCPT ); Tue, 25 Feb 2014 02:57:55 -0500 Message-ID: <530C4CAE.5000202@ti.com> Date: Mon, 24 Feb 2014 23:56:30 -0800 From: Russ Dill Organization: Texas Instruments User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Sebastian Capella , Russell King - ARM Linux CC: , , , , Andrew Morton , Thomas Gleixner , Will Deacon , Robin Holt Subject: Re: [PATCH RFC v1 1/3] ARM: Add irq disabled version of soft_restart. References: <1392774729-3235-1-git-send-email-sebastian.capella@linaro.org> <1392774729-3235-2-git-send-email-sebastian.capella@linaro.org> <20140222102616.GG21483@n2100.arm.linux.org.uk> <20140224231345.10580.62916@capellas-linux> In-Reply-To: <20140224231345.10580.62916@capellas-linux> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/24/2014 03:13 PM, Sebastian Capella wrote: > Quoting Russell King - ARM Linux (2014-02-22 02:26:17) >> On Tue, Feb 18, 2014 at 05:52:07PM -0800, Sebastian Capella wrote: >>> From: Russ Dill >>> >>> This adds the ability to run soft_restart with local_irq/fiq_disable >>> already called. This is helpful for the hibernation code paths. >> >> I'd rather keep this simple. There's no problem with calling soft_restart >> with interrupts already disabled. local_irq_disable()/local_fiq_disable() >> there should be harmless. > > Hi Russell, > > I'm observing a data abort loop when I replace this call: > > In the local_irq_disable, it ends up calling trace_hardirqs_off > (CONFIG_TRACE_IRQFLAGS_SUPPORT is enabled), which calls > trace_hardirqs_off_caller which checks lockdep_recursion in the > current task, but we've switched to a temporary stack with the > call_with_stack, and get_current is returning NULL. This > triggers a data abort, which calls trace_hardirqs_off > again and so on. > > Do you have any suggestions here? > > Thanks, > > Sebastian > So the alternative is to have a version of the call that calls a special no trace version of local_irq_disable()/local_fiq_disable(). Which would be preferable? Having a noirq version of soft_restart seems much simpler to me. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russ Dill Subject: Re: [PATCH RFC v1 1/3] ARM: Add irq disabled version of soft_restart. Date: Mon, 24 Feb 2014 23:56:30 -0800 Message-ID: <530C4CAE.5000202@ti.com> References: <1392774729-3235-1-git-send-email-sebastian.capella@linaro.org> <1392774729-3235-2-git-send-email-sebastian.capella@linaro.org> <20140222102616.GG21483@n2100.arm.linux.org.uk> <20140224231345.10580.62916@capellas-linux> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140224231345.10580.62916@capellas-linux> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Sebastian Capella , Russell King - ARM Linux Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, Will Deacon , linux-kernel@vger.kernel.org, Robin Holt , Andrew Morton , Thomas Gleixner , linux-arm-kernel@lists.infradead.org List-Id: linux-pm@vger.kernel.org On 02/24/2014 03:13 PM, Sebastian Capella wrote: > Quoting Russell King - ARM Linux (2014-02-22 02:26:17) >> On Tue, Feb 18, 2014 at 05:52:07PM -0800, Sebastian Capella wrote: >>> From: Russ Dill >>> >>> This adds the ability to run soft_restart with local_irq/fiq_disable >>> already called. This is helpful for the hibernation code paths. >> >> I'd rather keep this simple. There's no problem with calling soft_restart >> with interrupts already disabled. local_irq_disable()/local_fiq_disable() >> there should be harmless. > > Hi Russell, > > I'm observing a data abort loop when I replace this call: > > In the local_irq_disable, it ends up calling trace_hardirqs_off > (CONFIG_TRACE_IRQFLAGS_SUPPORT is enabled), which calls > trace_hardirqs_off_caller which checks lockdep_recursion in the > current task, but we've switched to a temporary stack with the > call_with_stack, and get_current is returning NULL. This > triggers a data abort, which calls trace_hardirqs_off > again and so on. > > Do you have any suggestions here? > > Thanks, > > Sebastian > So the alternative is to have a version of the call that calls a special no trace version of local_irq_disable()/local_fiq_disable(). Which would be preferable? Having a noirq version of soft_restart seems much simpler to me. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russ.Dill@ti.com (Russ Dill) Date: Mon, 24 Feb 2014 23:56:30 -0800 Subject: [PATCH RFC v1 1/3] ARM: Add irq disabled version of soft_restart. In-Reply-To: <20140224231345.10580.62916@capellas-linux> References: <1392774729-3235-1-git-send-email-sebastian.capella@linaro.org> <1392774729-3235-2-git-send-email-sebastian.capella@linaro.org> <20140222102616.GG21483@n2100.arm.linux.org.uk> <20140224231345.10580.62916@capellas-linux> Message-ID: <530C4CAE.5000202@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 02/24/2014 03:13 PM, Sebastian Capella wrote: > Quoting Russell King - ARM Linux (2014-02-22 02:26:17) >> On Tue, Feb 18, 2014 at 05:52:07PM -0800, Sebastian Capella wrote: >>> From: Russ Dill >>> >>> This adds the ability to run soft_restart with local_irq/fiq_disable >>> already called. This is helpful for the hibernation code paths. >> >> I'd rather keep this simple. There's no problem with calling soft_restart >> with interrupts already disabled. local_irq_disable()/local_fiq_disable() >> there should be harmless. > > Hi Russell, > > I'm observing a data abort loop when I replace this call: > > In the local_irq_disable, it ends up calling trace_hardirqs_off > (CONFIG_TRACE_IRQFLAGS_SUPPORT is enabled), which calls > trace_hardirqs_off_caller which checks lockdep_recursion in the > current task, but we've switched to a temporary stack with the > call_with_stack, and get_current is returning NULL. This > triggers a data abort, which calls trace_hardirqs_off > again and so on. > > Do you have any suggestions here? > > Thanks, > > Sebastian > So the alternative is to have a version of the call that calls a special no trace version of local_irq_disable()/local_fiq_disable(). Which would be preferable? Having a noirq version of soft_restart seems much simpler to me.