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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87F11EEAA50 for ; Thu, 14 Sep 2023 15:02:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234066AbjINPCb (ORCPT ); Thu, 14 Sep 2023 11:02:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231567AbjINPCb (ORCPT ); Thu, 14 Sep 2023 11:02:31 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD6101FC2; Thu, 14 Sep 2023 08:02:26 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4RmgWw1VMVz6K5sT; Thu, 14 Sep 2023 23:01:48 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Thu, 14 Sep 2023 16:02:24 +0100 Date: Thu, 14 Sep 2023 16:02:23 +0100 From: Jonathan Cameron To: James Morse CC: , , , , , , , , , Salil Mehta , Russell King , Jean-Philippe Brucker , , Subject: Re: [RFC PATCH v2 29/35] irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc() Message-ID: <20230914160223.0000782f@Huawei.com> In-Reply-To: <20230913163823.7880-30-james.morse@arm.com> References: <20230913163823.7880-1-james.morse@arm.com> <20230913163823.7880-30-james.morse@arm.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500006.china.huawei.com (7.191.161.198) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Wed, 13 Sep 2023 16:38:17 +0000 James Morse wrote: > gic_acpi_match_gicc() is only called via gic_acpi_count_gicr_regions(). > It should only count the number of enabled redistributors, but it > also tries to sanity check the GICC entry, currently returning an > error if the Enabled bit is set, but the gicr_base_address is zero. > > Adding support for the online-capable bit to the sanity check > complicates it, for no benefit. The existing check implicitly > depends on gic_acpi_count_gicr_regions() previous failing to find > any GICR regions (as it is valid to have gicr_base_address of zero if > the redistributors are described via a GICR entry). > > Instead of complicating the check, remove it. Failures that happen > at this point cause the irqchip not to register, meaning no irqs > can be requested. The kernel grinds to a panic() pretty quickly. > > Without the check, MADT tables that exhibit this problem are still > caught by gic_populate_rdist(), which helpfully also prints what > went wrong: > | CPU4: mpidr 100 has no re-distributor! > > Signed-off-by: James Morse > --- > drivers/irqchip/irq-gic-v3.c | 18 ++++++------------ > 1 file changed, 6 insertions(+), 12 deletions(-) > > diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c > index 72d3cdebdad1..0f54811262eb 100644 > --- a/drivers/irqchip/irq-gic-v3.c > +++ b/drivers/irqchip/irq-gic-v3.c > @@ -2415,21 +2415,15 @@ static int __init gic_acpi_match_gicc(union acpi_subtable_headers *header, > > /* > * If GICC is enabled and has valid gicr base address, then it means > - * GICR base is presented via GICC > + * GICR base is presented via GICC. The redistributor is only known to > + * be accessible if the GICC is marked as enabled. If this bit is not > + * set, we'd need to add the redistributor at runtime, which isn't > + * supported. > */ > - if (acpi_gicc_is_usable(gicc) && gicc->gicr_base_address) { > + if (gicc->flags & ACPI_MADT_ENABLED && gicc->gicr_base_address) Going in circles... > acpi_data.enabled_rdists++; > - return 0; > - } > > - /* > - * It's perfectly valid firmware can pass disabled GICC entry, driver > - * should not treat as errors, skip the entry instead of probe fail. > - */ > - if (!acpi_gicc_is_usable(gicc)) > - return 0; > - > - return -ENODEV; > + return 0; > } > > static int __init gic_acpi_count_gicr_regions(void)