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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 6421EC433C1 for ; Mon, 22 Mar 2021 10:32:10 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F36276199F for ; Mon, 22 Mar 2021 10:32:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F36276199F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=oOm3o5RPrsGozcGJEPcQdF2wlWHLcyEb+6cnqvKt7X0=; b=Sz/mDyVw5pAA1yYJrN8d20PDm p6Tw7Me+geCpjyxfSHWZeTnlDo7dGJKEqNaD97eI4ZV1OXMW4wws3C0nqxWYRSePuEUBtln16wDx7 WjKbxdMXCOG8b3Zi1SGIa8WaGq4ihUD5bRCnY0tchRbySCt6uLeQn+E/NIaTBdGjoJSicxbkgf6W3 5TbbuljwpBTjhUasypoEGd4kveAthBlnYnE9PaN3HfaJnnjMaIp+mQjOoHMtNuWxJVYcA4rR6Bquc 4Ehqp5lIZn4uDsIVQi9QUvm+L32ProGsxmrOCEF3BA+TazHlcl6ERwMSYH/VmCWmIJu8rx/Fj5FQS JvYl1Mkfg==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOHpQ-00BKs8-3m; Mon, 22 Mar 2021 10:30:32 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOHpI-00BKrS-J0 for linux-arm-kernel@lists.infradead.org; Mon, 22 Mar 2021 10:30:26 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 963211063; Mon, 22 Mar 2021 03:30:20 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.23.154]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B81A03F718; Mon, 22 Mar 2021 03:30:18 -0700 (PDT) Date: Mon, 22 Mar 2021 10:29:38 +0000 From: Mark Rutland To: Christoph Hellwig Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, james.morse@arm.com, marcan@marcan.st, maz@kernel.org, tglx@linutronix.de Subject: Re: [PATCHv3 2/6] arm64: don't use GENERIC_IRQ_MULTI_HANDLER Message-ID: <20210322102938.GA75892@C02TD0UTHF1T.local> References: <20210315115629.57191-1-mark.rutland@arm.com> <20210315115629.57191-3-mark.rutland@arm.com> <20210315192803.GB154861@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210315192803.GB154861@infradead.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210322_103024_905881_C0075F63 X-CRM114-Status: GOOD ( 20.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Christoph, On Mon, Mar 15, 2021 at 07:28:03PM +0000, Christoph Hellwig wrote: > On Mon, Mar 15, 2021 at 11:56:25AM +0000, Mark Rutland wrote: > > From: Marc Zyngier > > > > In subsequent patches we want to allow irqchip drivers to register as > > FIQ handlers, with a set_handle_fiq() function. To keep the IRQ/FIQ > > paths similar, we want arm64 to provide both set_handle_irq() and > > set_handle_fiq(), rather than using GENERIC_IRQ_MULTI_HANDLER for the > > former. > > Having looked through the series I do not understand this rationale > at all. You've only added the default_handle_irq logic, which seems > perfectly suitable and desirable for the generic version. The default_handle_irq thing isn't the point of the series, that part is all preparatory work. I agree that probably makes sense for the generic code, and I'm happy to update core code with this. The big thing here is that (unlike most architectures), with arm64 a CPU has two interrupt pins, IRQ and FIQ, and we need separate root handlers for these. That's what this series aims to do, and patches 1-5 are all preparatory work with that appearing in patch 6. Our initial stab at this did try to add that support to core code, but that was more painful to deal with, since you either add abstractions to make this look generic that make the code more complex for bot hthe genreic code and arch code, or you place arch-specific assumptions in the core code. See Marc's eariler stab at this, where in effect we had to duplicate the logic in the core code so that we didn't adversely affect existing entry assembly on other architectures due to the way the function pointers were stored. > Please don't fork off generic code for no good reason. I appreciate that this runs counter to the general goal of making things generic wherever possible, but I do think in this case we have good reasons, and the duplication is better than adding single-user abstractions in the generic code that complicate the generic code and arch code. Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel