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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47D6CC433F5 for ; Fri, 22 Oct 2021 10:05:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C4B5610D0 for ; Fri, 22 Oct 2021 10:05:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232527AbhJVKHv (ORCPT ); Fri, 22 Oct 2021 06:07:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:57978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231944AbhJVKHt (ORCPT ); Fri, 22 Oct 2021 06:07:49 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 24E4C611F2; Fri, 22 Oct 2021 10:05:32 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mdrQX-000tgG-V8; Fri, 22 Oct 2021 11:05:30 +0100 Date: Fri, 22 Oct 2021 11:05:29 +0100 Message-ID: <87o87hbcie.wl-maz@kernel.org> From: Marc Zyngier To: Mark Rutland Cc: linux-kernel@vger.kernel.org, aou@eecs.berkeley.edu, catalin.marinas@arm.com, deanbo422@gmail.com, green.hu@gmail.com, guoren@kernel.org, jonas@southpole.se, kernelfans@gmail.com, linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk, nickhu@andestech.com, palmer@dabbelt.com, paulmck@kernel.org, paul.walmsley@sifive.com, peterz@infradead.org, shorne@gmail.com, stefan.kristiansson@saunalahti.fi, tglx@linutronix.de, torvalds@linux-foundation.org, tsbogend@alpha.franken.de, vgupta@kernel.org, will@kernel.org Subject: Re: [PATCH 15/15] irq: remove handle_domain_{irq,nmi}() In-Reply-To: <20211021180236.37428-16-mark.rutland@arm.com> References: <20211021180236.37428-1-mark.rutland@arm.com> <20211021180236.37428-16-mark.rutland@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: mark.rutland@arm.com, linux-kernel@vger.kernel.org, aou@eecs.berkeley.edu, catalin.marinas@arm.com, deanbo422@gmail.com, green.hu@gmail.com, guoren@kernel.org, jonas@southpole.se, kernelfans@gmail.com, linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk, nickhu@andestech.com, palmer@dabbelt.com, paulmck@kernel.org, paul.walmsley@sifive.com, peterz@infradead.org, shorne@gmail.com, stefan.kristiansson@saunalahti.fi, tglx@linutronix.de, torvalds@linux-foundation.org, tsbogend@alpha.franken.de, vgupta@kernel.org, will@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 21 Oct 2021 19:02:36 +0100, Mark Rutland wrote: > > Now that entry code handles IRQ entry (including setting the IRQ regs) > before calling irqchip code, irqchip code can safely call > generic_handle_domain_irq(), and there's no functional reason for it to > call handle_domain_irq(). > > Let's cement this split of responsibility and remove handle_domain_irq() > entirely, updating irqchip drivers to call generic_handle_domain_irq(). > > For consistency, handle_domain_nmi() is similarly removed and replaced > with a generic_handle_domain_nmi() function which also does not perform > any entry logic. > > Previously handle_domain_{irq,nmi}() had a WARN_ON() which would fire > when they were called in an inappropriate context. So that we can > identify similar issues going forward, similar WARN_ON_ONCE() logic is > added to the generic_handle_*() functions, and comments are updated for > clarity and consistency. > > Signed-off-by: Mark Rutland > Cc: Marc Zyngier > Cc: Thomas Gleixner [...] > -/** > - * handle_domain_nmi - Invoke the handler for a HW irq belonging to a domain > - * @domain: The domain where to perform the lookup > - * @hwirq: The HW irq number to convert to a logical one > - * @regs: Register file coming from the low-level handling code > - * > - * This function must be called from an NMI context. > * > - * Returns: 0 on success, or -EINVAL if conversion has failed > - */ > -int handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq, > - struct pt_regs *regs) > + * This function must be called from an NMI context with irq regs > + * initialized. > + **/ > +int generic_handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq) > { > - struct pt_regs *old_regs = set_irq_regs(regs); > - int ret; > - > - /* > - * NMI context needs to be setup earlier in order to deal with tracing. > - */ > - WARN_ON(!in_nmi()); > - > - ret = generic_handle_domain_irq(domain, hwirq); > - > - set_irq_regs(old_regs); > - return ret; > + WARN_ON_ONCE(!in_nmi()); > + return handle_irq_desc(irq_resolve_mapping(domain, hwirq)); > } > -#endif > +EXPORT_SYMBOL_GPL(generic_handle_domain_nmi); nit: we don't need this export (only a root controller can handle NMIs), and that's the sort of thing I would really want to avoid exposing to modules. M. -- Without deviation from the norm, progress is not possible.