From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 26 Nov 2003 00:31:17 +0000 (GMT) Received: from gateway-1237.mvista.com ([IPv6:::ffff:12.44.186.158]:63736 "EHLO orion.mvista.com") by linux-mips.org with ESMTP id ; Wed, 26 Nov 2003 00:31:05 +0000 Received: (from jsun@localhost) by orion.mvista.com (8.11.6/8.11.6) id hAQ0V4501881; Tue, 25 Nov 2003 16:31:04 -0800 Date: Tue, 25 Nov 2003 16:31:04 -0800 From: Jun Sun To: Ralf Baechle Cc: "Kapoor, Pankaj" , linux-mips@linux-mips.org, jsun@mvista.com Subject: Re: MIPS Interrupts. Message-ID: <20031125163104.I28822@mvista.com> References: <37A3C2F21006D611995100B0D0F9B73C02C8FCAE@tnint11.telogy.design.ti.com> <20031125230946.GA12422@linux-mips.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20031125230946.GA12422@linux-mips.org>; from ralf@linux-mips.org on Wed, Nov 26, 2003 at 12:09:46AM +0100 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 3673 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: jsun@mvista.com Precedence: bulk X-list: linux-mips On Wed, Nov 26, 2003 at 12:09:46AM +0100, Ralf Baechle wrote: > On Tue, Nov 25, 2003 at 04:52:20PM -0500, Kapoor, Pankaj wrote: > > > Now there are 2 cases that can happen > > > > 1. Since we have not exited the ISR and the exception level has still not > > been restored there can be no more interrupts that are generated in the > > system. In such a case does that mean that the all bottom half handlers > > pending execution will run with interrupts disabled. > > NOTE: This does not seem likely because the local_irq_enable routine > > calls _sti which clears the exception level in the status register and > > also sets the IE bit. > > > > 2. If we have large number of tasklets or if the bottom half handlers take > > time to execute, then we could get another timer interrupt or other > > device interrupts causing context saves which would cause the stack to > > grow and CRASH the system. > > Interrupts are disabled while the respective interrupt handler is running. > They are re-enabled for "bottom halves", i.e., in do_softirq(). I think that is what the sender is worrying about. Jun