From patchwork Fri Jun 17 22:00:20 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Busch X-Patchwork-Id: 9185067 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3A417608A2 for ; Fri, 17 Jun 2016 22:00:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 203DF262AE for ; Fri, 17 Jun 2016 22:00:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 114B927F54; Fri, 17 Jun 2016 22:00:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6CCE0262AE for ; Fri, 17 Jun 2016 22:00:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755641AbcFQWAY (ORCPT ); Fri, 17 Jun 2016 18:00:24 -0400 Received: from mga14.intel.com ([192.55.52.115]:11303 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750986AbcFQWAX (ORCPT ); Fri, 17 Jun 2016 18:00:23 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP; 17 Jun 2016 15:00:24 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,485,1459839600"; d="scan'208";a="721154949" Received: from dcgshare.lm.intel.com ([10.232.118.254]) by FMSMGA003.fm.intel.com with ESMTP; 17 Jun 2016 15:00:22 -0700 Received: by dcgshare.lm.intel.com (Postfix, from userid 1017) id 6C55CE0C6D; Fri, 17 Jun 2016 16:00:22 -0600 (MDT) From: Keith Busch To: LKML , Thomas Gleixner , linux-pci@vger.kernel.org Cc: Bjorn Helgaas , Jon Derrick , Keith Busch Subject: [PATCH 1/2] irq: Add untracked irq handler Date: Fri, 17 Jun 2016 16:00:20 -0600 Message-Id: <1466200821-29159-1-git-send-email-keith.busch@intel.com> X-Mailer: git-send-email 1.7.1 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This adds a software irq handler for controllers that multiplex interrupts from multiple devices, but don't know which device generated the interrupt. For these devices, the irq handler that demuxes must check every action for every software irq using the same h/w irq in order to find out which device generated the interrupt. This will inevitably trigger spurious interrupt detection if we are noting the irq. The new irq handler does not track the handling for spurious interrupt detection. An irq that uses this also won't get stats tracked since it didn't generate the interrupt, nor added to randomness since they are not random. Signed-off-by: Keith Busch --- include/linux/irq.h | 1 + kernel/irq/chip.c | 43 +++++++++++++++++++++++++++++++++++++++++++ kernel/irq/handle.c | 18 ++++++++++++++---- kernel/irq/internals.h | 1 + 4 files changed, 59 insertions(+), 4 deletions(-) diff --git a/include/linux/irq.h b/include/linux/irq.h index 4d758a7..cd7b94e 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -482,6 +482,7 @@ extern void handle_fasteoi_irq(struct irq_desc *desc); extern void handle_edge_irq(struct irq_desc *desc); extern void handle_edge_eoi_irq(struct irq_desc *desc); extern void handle_simple_irq(struct irq_desc *desc); +extern void handle_untracked_irq(struct irq_desc *desc); extern void handle_percpu_irq(struct irq_desc *desc); extern void handle_percpu_devid_irq(struct irq_desc *desc); extern void handle_bad_irq(struct irq_desc *desc); diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 2f9f2b0..584e5e8 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -426,6 +426,49 @@ out_unlock: } EXPORT_SYMBOL_GPL(handle_simple_irq); +/** + * handle_untracked_irq - Simple and software-decoded IRQs. + * @desc: the interrupt description structure for this irq + * + * Untracked interrupts are sent from a demultiplexing interrupt + * handler when the demultiplexer does not know which device it its + * multiplexed irq domain generated the interrupt. IRQ's handled + * through here are not subjected to stats tracking, randomness, or + * spurious interrupt detection. + * + * Note: Like handle_simple_irq, the caller is expected to handle + * the ack, clear, mask and unmask issues if necessary. + */ +void handle_untracked_irq(struct irq_desc *desc) +{ + unsigned int flags = 0; + + raw_spin_lock(&desc->lock); + + if (!irq_may_run(desc)) + goto out_unlock; + + desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING); + + if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) { + desc->istate |= IRQS_PENDING; + goto out_unlock; + } + + desc->istate &= ~IRQS_PENDING; + irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS); + raw_spin_unlock(&desc->lock); + + __handle_irq_event_percpu(desc, &flags); + + raw_spin_lock(&desc->lock); + irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS); + +out_unlock: + raw_spin_unlock(&desc->lock); +} +EXPORT_SYMBOL_GPL(handle_untracked_irq); + /* * Called unconditionally from handle_level_irq() and only for oneshot * interrupts from handle_fasteoi_irq() diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index a15b548..d3f2490 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -132,10 +132,10 @@ void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action) wake_up_process(action->thread); } -irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) +irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags) { irqreturn_t retval = IRQ_NONE; - unsigned int flags = 0, irq = desc->irq_data.irq; + unsigned int irq = desc->irq_data.irq; struct irqaction *action; for_each_action_of_desc(desc, action) { @@ -164,7 +164,7 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) /* Fall through to add to randomness */ case IRQ_HANDLED: - flags |= action->flags; + *flags |= action->flags; break; default: @@ -174,7 +174,17 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) retval |= res; } - add_interrupt_randomness(irq, flags); + return retval; +} + +irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) +{ + irqreturn_t retval; + unsigned int flags = 0; + + retval = __handle_irq_event_percpu(desc, &flags); + + add_interrupt_randomness(desc->irq_data.irq, flags); if (!noirqdebug) note_interrupt(desc, retval); diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 09be2c9..d788150 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -83,6 +83,7 @@ extern void irq_mark_irq(unsigned int irq); extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr); +irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags); irqreturn_t handle_irq_event_percpu(struct irq_desc *desc); irqreturn_t handle_irq_event(struct irq_desc *desc);