Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934038AbcDTLKs (ORCPT ); Wed, 20 Apr 2016 07:10:48 -0400 Received: from hqemgate16.nvidia.com ([216.228.121.65]:10665 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932157AbcDTLEV (ORCPT ); Wed, 20 Apr 2016 07:04:21 -0400 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Wed, 20 Apr 2016 04:04:13 -0700 From: Jon Hunter To: Thomas Gleixner , Jason Cooper , Marc Zyngier , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Stephen Warren , Thierry Reding CC: Kevin Hilman , Geert Uytterhoeven , Grygorii Strashko , Lars-Peter Clausen , Linus Walleij , , , , , Jon Hunter Subject: [PATCH V2 02/14] irqchip/gic: WARN if setting the interrupt type for a PPI fails Date: Wed, 20 Apr 2016 12:03:45 +0100 Message-ID: <1461150237-15580-3-git-send-email-jonathanh@nvidia.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1461150237-15580-1-git-send-email-jonathanh@nvidia.com> References: <1461150237-15580-1-git-send-email-jonathanh@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2310 Lines: 52 Setting the interrupt type for private peripheral interrupts (PPIs) may not be supported by a given GIC because it is IMPLEMENTATION DEFINED whether this is allowed. There is no way to know if setting the type is supported for a given GIC and so the value written is read back to verify it matches the desired configuration. If it does not match then an error is return. There are cases where the interrupt configuration read from firmware (such as a device-tree blob), has been incorrect and hence gic_configure_irq() has returned an error. This error has gone undetected because the error code returned was ignored but the interrupt still worked fine because the configuration for the interrupt could not be overwritten. Given that this has done undetected and that failing to set the configuration for a PPI may not be a catastrophic, don't return an error but WARN if we fail to configure a PPI. This will allows us to fix up any places in the kernel where we should be checking the return status and maintain backward compatibility with firmware images that may have incorrect PPI configurations. Signed-off-by: Jon Hunter --- drivers/irqchip/irq-gic-common.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/irqchip/irq-gic-common.c b/drivers/irqchip/irq-gic-common.c index ffff5a45f1e3..9fa92a17225c 100644 --- a/drivers/irqchip/irq-gic-common.c +++ b/drivers/irqchip/irq-gic-common.c @@ -56,12 +56,15 @@ int gic_configure_irq(unsigned int irq, unsigned int type, /* * Write back the new configuration, and possibly re-enable - * the interrupt. If we fail to write a new configuration, - * return an error. + * the interrupt. WARN if we fail to write a new configuration + * and return an error if we failed to write the configuration + * for an SPI. If we fail to write the configuration for a PPI + * this is most likely because the GIC does not allow us to set + * the configuration and so it is not a catastrophic failure. */ writel_relaxed(val, base + GIC_DIST_CONFIG + confoff); - if (readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val) - ret = -EINVAL; + if (WARN_ON(readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val)) + ret = irq < 32 ? 0 : -EINVAL; if (sync_access) sync_access(); -- 2.1.4