From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB34CC2D0A3 for ; Sun, 1 Nov 2020 14:33:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E4502158C for ; Sun, 1 Nov 2020 14:33:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726752AbgKAOdK convert rfc822-to-8bit (ORCPT ); Sun, 1 Nov 2020 09:33:10 -0500 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:29753 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726370AbgKAOdJ (ORCPT ); Sun, 1 Nov 2020 09:33:09 -0500 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-19-MaBuzPe6NymqWwm9BDgSpA-1; Sun, 01 Nov 2020 14:33:06 +0000 X-MC-Unique: MaBuzPe6NymqWwm9BDgSpA-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Sun, 1 Nov 2020 14:33:05 +0000 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Sun, 1 Nov 2020 14:33:05 +0000 From: David Laight To: 'Marc Zyngier' , LAK , linux-kernel CC: Will Deacon , Catalin Marinas , Thomas Gleixner , Valentin Schneider , Peter Zijlstra , "Android Kernel Team" Subject: RE: [PATCH 1/2] genirq: Allow an interrupt to be marked as 'naked' Thread-Topic: [PATCH 1/2] genirq: Allow an interrupt to be marked as 'naked' Thread-Index: AQHWsFD9Rnig6/7CxEqjPXAUWe/UuKmzVn2w Date: Sun, 1 Nov 2020 14:33:05 +0000 Message-ID: <83451f88a17e4a63ab5b523f8f817970@AcuMS.aculab.com> References: <20201101131430.257038-1-maz@kernel.org> <20201101131430.257038-2-maz@kernel.org> In-Reply-To: <20201101131430.257038-2-maz@kernel.org> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marc Zyngier > Sent: 01 November 2020 13:14 > > Some interrupts (such as the rescheduling IPI) rely on not going through > the irq_enter()/irq_exit() calls. To distinguish such interrupts, add > a new IRQ flag that allows the low-level handling code to sidestep the > enter()/exit() calls. > > Only the architecture code is expected to use this. It will do the wrong > thing on normal interrupts. > > Signed-off-by: Marc Zyngier > --- > include/linux/irq.h | 4 +++- > kernel/irq/debugfs.c | 1 + > kernel/irq/irqdesc.c | 17 ++++++++++++----- > kernel/irq/settings.h | 7 +++++++ > 4 files changed, 23 insertions(+), 6 deletions(-) > ... > diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c > index 1a7723604399..c08a1c19d061 100644 > --- a/kernel/irq/irqdesc.c > +++ b/kernel/irq/irqdesc.c > @@ -667,10 +667,9 @@ int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq, > { > struct pt_regs *old_regs = set_irq_regs(regs); > unsigned int irq = hwirq; > + struct irq_desc *desc; > int ret = 0; > > - irq_enter(); > - > #ifdef CONFIG_IRQ_DOMAIN > if (lookup) > irq = irq_find_mapping(domain, hwirq); > @@ -680,14 +679,22 @@ int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq, > * Some hardware gives randomly wrong interrupts. Rather > * than crashing, do something sensible. > */ > - if (unlikely(!irq || irq >= nr_irqs)) { > + desc = irq_to_desc(irq); > + if (unlikely(!desc || irq >= nr_irqs)) { Should those tests be in the other order? Probably as: if (unlikely(irq >= nr_irqs || !(desc = irq_to_desc(irq))) { ... David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)