From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752293Ab0G1F1O (ORCPT ); Wed, 28 Jul 2010 01:27:14 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:55000 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751601Ab0G1F1K (ORCPT ); Wed, 28 Jul 2010 01:27:10 -0400 Message-ID: <4C4FBEDC.4000008@monstr.eu> Date: Wed, 28 Jul 2010 07:23:40 +0200 From: Michal Simek Reply-To: monstr@monstr.eu User-Agent: Thunderbird 2.0.0.22 (X11/20090625) MIME-Version: 1.0 To: Mike Frysinger CC: Andrew Morton , rostedt@goodmis.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@elte.hu, linux-arch@vger.kernel.org Subject: Re: [PATCH] asm-generic: Use raw_local_irq_save/restore instead local_irq_save/restore References: <1274863724-14906-1-git-send-email-monstr@monstr.eu> <1274863724-14906-2-git-send-email-monstr@monstr.eu> <1274884963.22648.245.camel@gandalf.stny.rr.com> <20100526100805.171b3c48.akpm@linux-foundation.org> <4C4D4C2E.8010103@monstr.eu> <20100727161819.cf6feab1.akpm@linux-foundation.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mike Frysinger wrote: > On Tue, Jul 27, 2010 at 19:18, Andrew Morton wrote: >> On Mon, 26 Jul 2010 10:49:50 +0200 Michal Simek wrote: >>> start/stop_critical_timing function for preemptirqsoff, preemptoff >>> and irqsoff tracers contains atomic_inc and atomic_dec operations. >>> >>> Atomic operations used local_irq_save/restore macros to ensure >>> atomic access but they are traced by the same function which is causing >>> recursion problem. >>> >>> The reason is when these tracers are turn ON then local_irq_save/restore >>> macros are changed in include/linux/irqflags.h to call trace_hardirqs_on/off >>> which call start/stop_critical_timing. >>> >>> Microblaze was affected because use generic atomic implementation. >> Seems that this will also affect blackfin, mn10300 and score. I guess >> they aren't supporting tracing yet? > > do you mean TRACE_IRQFLAGS_SUPPORT ? Blackfin should ... my > understanding was that arches just needed to implement asm/irqflags.h > for it. Blackin uses own include/asm/atomic.h implementation where shouldn't be a problem with irqflags tracer. Look at my second post. Michal -- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/ Microblaze U-BOOT custodian