Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964798Ab0GPJbw (ORCPT ); Fri, 16 Jul 2010 05:31:52 -0400 Received: from snt0-omc1-s39.snt0.hotmail.com ([65.54.61.76]:17575 "EHLO snt0-omc1-s39.snt0.hotmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936078Ab0GPJbu (ORCPT ); Fri, 16 Jul 2010 05:31:50 -0400 X-Greylist: delayed 369 seconds by postgrey-1.27 at vger.kernel.org; Fri, 16 Jul 2010 05:31:50 EDT X-Originating-IP: [94.195.177.167] X-Originating-Email: [johnkyr83@hotmail.com] Message-ID: From: "limp" To: Subject: Where system interrupts get disabled at LAPIC timer handler execution? Date: Fri, 16 Jul 2010 10:25:32 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcskyNbV2W94SvyyS/2f4n5xwWizRQ== Content-Language: en-gb X-OriginalArrivalTime: 16 Jul 2010 09:25:40.0337 (UTC) FILETIME=[DB696E10:01CB24C8] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1032 Lines: 28 Dear all, I am trying to demystify what happens when the kernel has configured to use LAPIC timer as its timer and I've ran into some problems/questions. AFAIK, when a LAPIC timer interrupt occurs, the assembly wrapper at enrty_32.s jumps the execution at smp_apic_timer_interrupt(). At the beginning of this function, I've checked to see if interrupts are enabled or not using irqs_disabled() and I found out that they are disabled. The problem is that I can't find where Linux disables interrupts before calling smp_apic_timer_interrupt(). The only place this could be done is in the assembly wrapper but I can't really find it. Does the processor disables interrupts by default when a LAPIC timer interrupt occurs? Any help will be much appreciated. Thanks in advance. John. -- 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/