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=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 35FEDC4361B for ; Tue, 8 Dec 2020 09:52:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E27A7233FA for ; Tue, 8 Dec 2020 09:52:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728770AbgLHJwR (ORCPT ); Tue, 8 Dec 2020 04:52:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:51184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726338AbgLHJwQ (ORCPT ); Tue, 8 Dec 2020 04:52:16 -0500 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 C19F123A82; Tue, 8 Dec 2020 09:51:35 +0000 (UTC) Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94) (envelope-from ) id 1kmZef-00H37M-Iw; Tue, 08 Dec 2020 09:51:33 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 08 Dec 2020 09:51:33 +0000 From: Marc Zyngier To: Pingfan Liu Cc: linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Thomas Gleixner , Mark Rutland , LKML Subject: Re: [PATCH] arm64/irq: report bug if NR_IPI greater than max SGI during compile time In-Reply-To: References: <1607419304-26140-1-git-send-email-kernelfans@gmail.com> <0f230af42ff4c6e4cf763b9145fb9487@kernel.org> User-Agent: Roundcube Webmail/1.4.9 Message-ID: <867be4df47247f8c56687cf2046ee7bb@kernel.org> X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: kernelfans@gmail.com, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de, mark.rutland@arm.com, linux-kernel@vger.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 2020-12-08 09:43, Pingfan Liu wrote: > On Tue, Dec 8, 2020 at 5:31 PM Marc Zyngier wrote: >> >> On 2020-12-08 09:21, Pingfan Liu wrote: >> > Although there is a runtime WARN_ON() when NR_IPR > max SGI, it had >> > better >> > do the check during built time, and associate these related code >> > together. >> > >> > Signed-off-by: Pingfan Liu >> > Cc: Catalin Marinas >> > Cc: Will Deacon >> > Cc: Thomas Gleixner >> > Cc: Jason Cooper >> > Cc: Marc Zyngier >> > Cc: Mark Rutland >> > To: linux-arm-kernel@lists.infradead.org >> > Cc: linux-kernel@vger.kernel.org >> > --- >> > arch/arm64/kernel/smp.c | 2 ++ >> > drivers/irqchip/irq-gic-v3.c | 2 +- >> > drivers/irqchip/irq-gic.c | 2 +- >> > include/linux/irqchip/arm-gic-common.h | 2 ++ >> > 4 files changed, 6 insertions(+), 2 deletions(-) >> > >> > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c >> > index 18e9727..9fc383c 100644 >> > --- a/arch/arm64/kernel/smp.c >> > +++ b/arch/arm64/kernel/smp.c >> > @@ -33,6 +33,7 @@ >> > #include >> > #include >> > #include >> > +#include >> > >> > #include >> > #include >> > @@ -76,6 +77,7 @@ enum ipi_msg_type { >> > IPI_WAKEUP, >> > NR_IPI >> > }; >> > +static_assert(NR_IPI <= MAX_SGI_NUM); >> >> I am trying *very hard* to remove dependencies between the >> architecture >> code and random drivers, so this kind of check really is >> counter-productive. >> >> Driver code should not have to know the number of IPIs, because there >> is >> no requirement that all IPIs should map 1:1 to SGIs. Conflating the >> two > > Just curious about this. Is there an IPI which is not implemented by > SGI? Or mapping several IPIs to a single SGI, and scatter out due to a > global variable value? We currently have a single NS SGI left, and I'd like to move some of the non-critical IPIs over to dispatching mechanism (the two "CPU stop" IPIs definitely are candidate for merging). That's not implemented yet, but I don't see a need to add checks that would otherwise violate this IPI/SGI distinction. Thanks, M. -- Jazz is not dead. It just smells funny...