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,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 7CF21C4361B for ; Tue, 8 Dec 2020 14:06:02 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 3401723AFE for ; Tue, 8 Dec 2020 14:06:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3401723AFE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-ID:References:In-Reply-To:Subject:To:From: Date:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=kV63KdTOisMAzFOjM1qe2tOqzYVz2pSqtfOC5poXK6A=; b=m44K0vcJe8VG/bSfNg8RfDdv7 RxAX9ryZcBipSeLx3ZxNMZBVEETWJ9wkjFidb1WxyV8gAQGMwT265aAB/bn7+YMmhbQt6KglhGzLu vxsTZhLU9UvpEFotbqcErCD3AmhdFA4zbxH47s7SwqfDdpeqaKo4WBMzjXIOEr617wllnT+KAND9F KEFk+IxdwzTriM5yxAxTwGovjjoZ/4L6/s+I5JJhO2Yq4eYjJqKz1WLZknfzRn/FoIJBEYqRyIcIg 8KlSDz5ZCAbZjaoQJhfwj59T2guA12FNZ7lKmZ0gxwNZvGp76ZxWtOB3RXt81yAvQ6NOOuECaa5+G LI9b/ZHMw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kmdbr-0002T1-CN; Tue, 08 Dec 2020 14:04:55 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kmdbo-0002SC-3q for linux-arm-kernel@lists.infradead.org; Tue, 08 Dec 2020 14:04:52 +0000 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 3E28423AC4; Tue, 8 Dec 2020 14:04:51 +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 1kmdbl-00H6Ai-1g; Tue, 08 Dec 2020 14:04:49 +0000 MIME-Version: 1.0 Date: Tue, 08 Dec 2020 14:04:49 +0000 From: Marc Zyngier To: Pingfan Liu Subject: Re: [PATCH] arm64/irq: use NMI to send stop IPI In-Reply-To: <1607433270-9807-1-git-send-email-kernelfans@gmail.com> References: <1607433270-9807-1-git-send-email-kernelfans@gmail.com> User-Agent: Roundcube Webmail/1.4.9 Message-ID: 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, mark.rutland@arm.com, julien.thierry@arm.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201208_090452_254059_43964592 X-CRM114-Status: GOOD ( 11.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Julien Thierry Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020-12-08 13:14, Pingfan Liu wrote: > Like other arches, both 'kexec -l' and 'kexec -p' expect to use NMI to > interrupt other cpus in order to capture cpus tightly to a known state. > > So for both of the cases, try to use NMI IPI if irqchip supports NMI. There are at least 2 other competing series doing the same thing, and (ab)using NMIs for dubious purposes (kexec, kgdb...) (1) Please work with others instead of reinventing things from scratch, with similar problems (2) No additional NMI patches will make it until we have resolved the issues described in [1], which is likely to take some time Thanks, M. [1] https://lore.kernel.org/linux-arm-kernel/87lfewnmdz.fsf@nanos.tec.linutronix.de/ -- Jazz is not dead. It just smells funny... _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel