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=-10.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 9A935C47094 for ; Thu, 10 Jun 2021 16:30:28 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 5F4DC611B0 for ; Thu, 10 Jun 2021 16:30:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F4DC611B0 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=bombadil.20210309; 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=1fE+5a7939TnuogeIakS5mXw1aB9eSy329ftbW4YozE=; b=b+Q84vcC6bbNdH cQpOiv8k/VleEc2hwm9ZuElTlMghp2xVfanqceYAe22FmiBzQYYcRTYmcz2Dew1B7hNkCgvB5KsV0 5mOsUpXsbFiT8Rn3CvTWJYvqxvaxFZXgAyk81LZ64gYC6j8GTxVudUQk5ADd6YJM9BBqfIjVDJBs/ tpZTIkvaFSXO6YX/u0OGz4sMXjLGtpkKNE0ybzSzxopLbRdyq0OPzProBppx6Fw5TvuHW2AN9obGh KVbS4p+4un10t5BEcoCyiX7xlYBgERtgguGDl4A73ow80qXT/hFUWIyvRGrGwn3Q9vy/SBSLNNg/G seOCfctcdhMy7ZNwHRGQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lrNXw-001fof-9D; Thu, 10 Jun 2021 16:28:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lrNXm-001fmM-KF for linux-arm-kernel@lists.infradead.org; Thu, 10 Jun 2021 16:28:36 +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 94B08ED1; Thu, 10 Jun 2021 09:28:29 -0700 (PDT) Received: from lpieralisi (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5C7E13F719; Thu, 10 Jun 2021 09:28:28 -0700 (PDT) Date: Thu, 10 Jun 2021 17:28:23 +0100 From: Lorenzo Pieralisi To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, Will Deacon , Catalin Marinas , Mark Rutland , Valentin Schneider , Alexandru Elisei , Russell King , kernel-team@android.com Subject: Re: [PATCH 0/3] arm64: Fix cpuidle with pseudo-NMI enabled Message-ID: <20210610162823.GA20025@lpieralisi> References: <20210608172715.2396787-1-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210608172715.2396787-1-maz@kernel.org> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210610_092834_752766_D91243C7 X-CRM114-Status: GOOD ( 22.22 ) 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 On Tue, Jun 08, 2021 at 06:27:12PM +0100, Marc Zyngier wrote: > It appears that although cpu_do_idle() is correctly dealing with the > PMR/DAIF duality, the PSCI cpu-suspend code has been left unaware of > it. > > On a system that uses PSCI for idle (such as the Ampere Altra I have > access to), the kernel dies as soon as it enters idle (interrupts are > off at the GIC CPU interface level). Boo. After investigating a bit I realised that this should depend on ICC_CTLR_EL3.PMHE - if that's clear the PMR should not affect the GICR->CPU IRQ forwarding (or WakeRequest signal generation when the GICR_WAKER.ProcessorSleep==1). IIUC if PMHE == 0, the PMR plays no role in wfi completion (and WakeSignal generation for a CPU/GICR in quiescent state). I assume on Ampere Altra PMHE == 1. This changes almost nothing to the need for this patchset but at least we clarify this behaviour. Also, we should not be writing ICC_PMR_EL1 when GICR_WAKER.ProcessorSleep == 1 (which may be set in gic_cpu_pm_notifier()), this can hang the system. I wonder whether this arm_cpuidle_{save,restore}_context() should be moved into the gic_cpu_pm_notifier() itself - which would solve also the PSCI suspend issue Sudeep raised - it would be a bit ugly though (CPU PM notifiers are run in S2R and CPUidle automatically and this would work for any S2R/CPUidle backend other than PSCI even though that does not/will never exist on arm64 ;-)) https://lore.kernel.org/linux-arm-kernel/20210608182044.ayqa6fbab4jyz7kp@bogus I still believe this series is right - just raised these points for discussion. Thanks, Lorenzo > Instead of spreading more magic code around, I've elected to provide a > pair of helpers (arm_cpuidle_{save,restore}_context()) which do the > heavy lifting. > > With that in place, I can finally boot the above system with > irqchip.gicv3_pseudo_nmi=1. I'd welcome feedback from people who may > have experienced similar issues in the past (and on different > machines). > > Marc Zyngier (3): > arm64: Add cpuidle context save/restore helpers > arm64: Convert cpu_do_idle() to using cpuidle context helpers > PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter() > > arch/arm/include/asm/cpuidle.h | 5 ++++ > arch/arm64/include/asm/cpuidle.h | 35 +++++++++++++++++++++++++++ > arch/arm64/kernel/process.c | 41 +++++++------------------------- > drivers/firmware/psci/psci.c | 5 ++++ > 4 files changed, 54 insertions(+), 32 deletions(-) > > -- > 2.30.2 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel